Math teaching in general

Math teaching strategies #3: Teach computation procedures using consistent language

Posted on by Dr. Don

Improv can be entertaining, but it will frustrate students trying learn a procedure.

Much of math, and especially computation, is about learning a process or a set of procedures. [I am assuming you are practical enough to know that we cannot expect elementary aged children to re-discover all of mathematics on their own, as some people recommend.]

Learning a procedure means knowing “What’s next?”  If you ever learned a procedure (for example a recipe) you know that it is between steps, when you ask yourself, “What’s next?” that you need help from the written recipe.  Students are no different.  Just showing them what to do is usually not enough for them to be able to follow in your footsteps.  You need to teach them the steps of the procedure.  As with anything you teach, you are going to confuse your students if you do things in a different order, or with different words, or different steps.  What you call things, and some of how you explain yourself, and some of the sequence of doing the procedure is arbitrary.  If you are improvising you will do things differently each time and your students will be confused.  At a minimum you need  it written down.

Math teaching strategy: Use a script or a process chart to keep the instructions consistent.

We know a lot about how to help students learn a procedure.  We know we need to consistently follow the same set of steps in the same order, until students have learned it.  We know we need to explicitly tell students the decisions they must make while working so they know what to do and when, in other words, we have to make our thinking process overt.  We know we need to be consistent in our language of instruction so that students benefit from repetition of examples.  And finally, we know we need to careful in our selection of problems so that we demonstrate with appropriate examples how the new process works and where it does not work.

Guess what?  You can’t do all of that when you are improvising your instruction and making up the directions on the fly. To be able to do all that, you need a script and pre-selected examples.  Many teachers have been taught to use a chart of steps, posted in their classroom, to which they refer as they model a procedure.  The same effect can be achieved with a script, so that the teacher uses the same wording along with the same steps in the same order.  If you improvise, it won’t always be the same, which will confuse your students.

You have to learn when and how to make decisions.  Every math procedure involves looking at the situation and making decisions about what and how to do what needs to be done.  You have to know what operation to use, when to borrow, when to carry, where to write each digit and so on.  Because you as the teacher already know how to do the procedure, it is tricky to remember to explain your thinking.

Math teaching strategy: Teach a consistent rule for every decision students must make.

Good teaching involves first explaining your decision-making and then giving your students practice in making the right decision in the given circumstances and finally to make them explain why–using the rule you used in the first place.   First, you teach something like, “Bigger bottom borrows” to help students decide when to borrow.  Then you prompt them to explain how they know whether or not to borrow.  All of that should be asked and answered in the right place and at the right time.  A script or a posted process chart will help you remember all the decisions that have to be made, and what to look at to make the right one.  Without a script it is very unlikely that you will remember the exact wording each time.  You need a script to be able to deliver consistent language of instruction.

Math teaching strategy: Plan ahead to carefully choose the right examples. 

With some math procedures it is quite hard to choose the right examples.  The fine points can be obscured when the examples the teacher happens to come up with, are not quite right.  The examples may be an exception or handled differently in a way the procedure has not taught.  So for example borrowing across a zero is different than across other numerals so the numbers in a minuend must be chosen carefully rather than off the cuff.

Also, when teaching a procedure it is essential to teach when to use the procedure and when not to use that procedure.  It is important that the teacher present “non-examples,” that is, problems in which you don’t follow that procedure.  I have seen students who are taught, for example, borrowing, using only examples that need borrowing.  Then they turn around and borrow in every problem–because that is what they were taught.  They should have been taught with a few non-examples mixed in, that is, problems where borrowing wasn’t necessary so they learned correctly when to borrow as well as how to borrow.   Choosing teaching examples on the fly will often end up with more confusion rather than less.

If it bothers you to see students as frustrated as the one above, then find* or write out a script for teaching computation so that you can be consistent and effective.  Trust me, your students will love you for it.

* You may want to look at the “Learning Computation” programs within the Rocket Math Universal subscription.  Here are links to blogs on them:  Addition, Subtraction, and Multiplication.  These are sensible, small steps, clearly and consistently scripted so each skill builds on the next.

Math Teaching strategy #4: Teach only one procedure at a time

Posted on by Dr. Don

It’s far better to know only one way to get there, than to get lost every time!

There are educational gurus out there promoting the idea that by giving students multiple solution paths it will give them a deeper understanding of math.  Generally these experts know this from teaching pre-service teachers in college, some of whom come to have some insights by learning multiple paths to the same goal.  Sorry folks.  What works for pre-service teachers in college, does not [and never will] apply to most children.

True, there are multiple ways to solve most arithmetic problems.  They have been discovered over centuries across multiple civilizations.  While one might dream of knowing all the ways to do long division, it’s far better to have one reliable method learned than to simply be confused and to get lost each time.  Just as in directions to go someplace, it is hard to remember all the steps in the directions.  When you’re new to a destination, the lefts and the rights are all arbitrary.  If you get two or more sets of directions, you are going to mix the steps from one way with the steps from the other method and you will not arrive at your destination.

Math teaching strategy: Teach one solution method and stick to that until everyone has it mastered.

In real life, as in math, once you learn one reliable method of getting to your destination, you are then free to learn additional ways, or to try short cuts.  But please don’t confuse a beginning learner with short cuts or alternative methods.  It adds to the memory load and there are additional things to think about when trying alternatives.  Before the learner is solid in one method, the new information is likely going to get mixed up with the not-yet-learned material, leading to missteps and getting lost. Teach the long way every time and leave them to finding the short cuts on their own time.

But teachers say, “I want them to have a holistic understanding of what they are doing!”  Which is laudable, but that understanding has to come AFTER a reliable set of procedures is mastered.  There’s no reason that additional learning can’t be added to the student’s knowledge base, but it can’t come before or in place of learning a simple, basic, reliable procedure.   These admirable goals of getting a deeper understanding of math are fine, but they require MORE teaching than what used to be done, back when we were only taught algorithms for arithmetic.  There is time to learn more than the algorithms, if we teach effectively and efficiently.  Unfortunately, the deeper and more profound understandings in math can’t precede or be substituted for teaching the algorithms.

If you don’t believe me, ask a typical middle school student to do some arithmetic for you these days.  Few of them have mastered any reliable procedures for doing long division or converting mixed numbers or adding unlike fractions, etc.  It’s time to accept that teaching one way of doing things is better than none.

Math Teaching strategies #5: Separate the introduction of similar concepts

Posted on by Dr. Don

Teaching two similar concepts and their vocabulary terms at the same time creates confusion.

The classic example is teaching parallel and perpendicular on the same day.  The two concepts have to do with orientation of lines and the new vocabulary terms for them are similar.  So teaching them at the same time means some or many students will have the two terms confused for a long time.  That is known as a chronic confusion–possibly permanent.  They will know that orientation of lines is one of those two terms, possibly, but will be confused about which is which.  The predictable conversation with the teacher goes thusly:

Teacher:  See these two lines lines.  Are they parallel or perpendicular?

Student: I think they’re perpendicular.

Teacher: Well…

Student: No, wait! I know.  They’re parallel.

Teacher: Yes, you’re right.  I’m glad you’ve learned that.

In case you missed it, the above student did NOT know the correct term.  The student just knew it was one of two terms, but unsure as to which one.  So the student picked one and as soon as there wasn’t confirmation by the teacher, switched to the other term.  When you’re busy teaching it is easy to get fooled by that kind of response into assuming the students really did learn it.

Other examples abound in math.  Teaching numerator and denominator in the same lesson is common.  Teaching the terms proper fractions and improper fractions on the same day is another example.  Acute and obtuse angles are yet another pair of chronically confused concepts that are introduced simultaneously.

Math teaching strategies: Separate the introduction of similar concepts in time.

If you teach one concept and only one of the pair, there’s no cause for confusion.  It will still take a lot of repetition and practice for it to be cemented into memory, but students will be clear.  If they use the term, for example parallel a lot of times in conjunction with examples they will soon (in a couple of weeks) be able to recall.  However, you should pair the concept with non-examples of the concept.  Not the opposite necessarily but just not an example of the concept.

For example: For the picture to the right you would ask the students.

A “Are the two lines in item A parallel or not parallel?”   Ans: Not parallel.

B “Are the two lines in item B parallel or not parallel?”   Ans: Parallel.

C “Are the two lines in item C parallel or not parallel?”   Ans: Not parallel.

Then after a couple of weeks you could introduce perpendicular.  Again teach it on its own and then contrasted with non-examples until the vocabulary was clear. Probably for a couple of weeks.   Only then can you combine both terms in the same lesson.

Another advantage of this approach is that you have avoided the other common mistake.  Students sometimes come to the conclusion that all pairs of lines are either parallel or perpendicular.  This method of introducing the concepts helps them realize that there are non-examples of each concept, parallel lines and ones that aren’t as well as perpendicular lines and ones that aren’t as well.

 

Math teaching strategies #6: Teaching a new concept using a common sense name

Posted on by Dr. Don

 

Here’s an example of the problem.   A brachistochrone (pictured above) is a curve between two points along which a body can move under gravity in a shorter time than for any other curve. It is the same curve as a cycloid, but just hanging downward.   A cycloid is the path traced by a point on a wheel as the wheel rolls, without slipping, along a flat surface. The standard parametrization is x = a(t – sin t),y = a(1 – cos t), where a is the radius of the wheel.

Introducing this concept and the term brachistochrone at the same time would be designed so the teacher can use brachistochrone and its concept in instruction.  However, because the term is new and the concept is also new, when the teacher uses the new term during later instruction, the students will have difficulty bringing the concept into their minds. “So a brachistochrone has some other cool properties. What’s the primary thing we know about the brachistochrone?”

Instruction not working.  If you watch instruction where the term and the concept have been taught simultaneously, confusion ensues when the teacher uses the term.  You’ll see students looking away as they try to bring up the explanation of that weird new term in their memory (see the pictured example?).  Sometimes the teacher will notice this and give a thumbnail definition or example of the term, and the students will then remember.  However, the teacher should then realize that the concept was not connected to the new vocabulary term.

Math teaching strategies: Teach new concepts using a common sense term at first.  

When a new vocabulary term is used to introduce a new concept, students will need a lot of practice with recalling the term and the definition before it can be used in instruction.  On the other hand, students can quickly understand and use new concepts and ideas in math if they don’t have to learn a new word for it.  Using a common sense term, the idea or concept can be worked with, the implications studied and it can be applied to real world problems almost immediately.  Students can later quite easily learn proper vocabulary terms for concepts they understand and recognize.  Here’s an example. 

The “shortest time curve.”  It is more efficient and effective to teach the concept first and use a common sense term for it.  I would call a brachistochrone the “shortest time curve.”**  Instruction would proceed with the, “Do you remember that ‘shortest time curve’ we talked about last week?”  Students would easily be able to remember it.  Instruction would go like this: “So ‘the shortest time curve’ has some other cool properties. What’s the primary thing we know about the ‘shortest time curve’?”  Students would easily be able to answer this question.

Then after students have worked with the concept of “the shortest time curve” for a couple of weeks, you can add the vocabulary term to it. “By the way, the proper mathematical name for “the shortest time curve” is called a brachistochrone. Isn’t that cool?”  Students will want to learn its proper name as a point of pride about knowing this fancy term for a concept they already “own,” rather than a point of confusion.

**Actually that’s what brachistochrone means in Greek: brakhistos, meaning shortest and khronos meaning time.

 

What if teachers won’t do Rocket Math?

Posted on by Dr. Don

Don’t argue, just prove it works! 

Joyce asks: 

How can we encourage the teacher who refuses rocket math and administration does not reinforce (or enforce) the program’s use?

Dr. Don’s response:

  Joyce,

     This is a great question.  Frankly, one of the most annoying things I found during my time as a teacher were the constant “new” fads.  I got sick and tired of being told to do things I knew would not work.  I don’t blame people for being skeptical or an administration that won’t go to bat for a new curriculum.  I think it is the responsible thing to do. Which is why schools should test everything for themselves, which isn’t that hard to do.  Prove to yourself it works with your students in your school with your staff.  Then you know it is worth doing.  Only then do you have a responsibility to reinforce the program’s use, only after it is proven.
In one of the first schools to use Rocket Math we had a veteran teacher who said she did not think Rocket Math would be any better than the things she had been doing to help her students learn math facts for years.  The principal wisely allowed as how that might be possible, but asked if she would be willing to test her assertion.  Rocket Math has 2-minute timings of all the facts which the students take every couple of weeks.  The principal asked if she would give that test to her students at the beginning and the end of the year and compare her results with that of other classes.  She agreed.  At the end of year the Rocket Math students were far higher in their fluency than her students, even though at the beginning of the year her students had been more fluent than the other students.  At that point she said, “Well this proves it to me.  I’ll be using Rocket Math next year.”
   Just use those 2-minute timings as pre and post tests and see if there is anything that will beat Rocket Math.  Any teacher worth their salt should want to use a curriculum that is effective and helps students learn.
I have the following standing offer on my website.  If any school will conduct research comparing Rocket Math to some other method of practicing math facts and share your results–I will refund half of the purchase price of the curriculum.  If a school finds some other method is more effective, I will refund 100% of your purchase price.

Don’t cause confusion: teach only one operation at a time.

Posted on by Dr. Don

Don’t switch back and forth between all addition facts and all subtraction facts

Teachers often ask me if they can start Rocket Math and do both addition and subtraction at the same time–to help their students catch up quicker. No, don’t do it! It will cause special kinds of confusion (called proactive and retroactive inhibition) as students try to memorize the relationships among the numbers.

Students learning only addition for example, are learning one number family 5*3=8 and 3*5=8. So 5 and 3, no matter which order you put them, they go with 8. That’s pretty easy, no way to get confused. But if students are learning subtraction facts at the same time they have a lot more to remember. On top of learning which numbers go together students have to learn which operation is going on. They also have to remember that 5*3 is sometimes 8, and sometimes 5*3 is 2. And 8*3 is sometimes 11 and sometimes 5 depending on which operation is going on. Switching back and forth from addition to subtraction adds a layer of confusion. It does not make it impossible, it just makes it harder because it is a little more confusing. If you teach only one operation at a time students will find it much easier and they will learn faster and be more successful. That is what we want after all, right?

Can you teach through Fact Families?

Yes, you can. If students learn facts in families (3+2=5, 2+3=5, 5-2=3, 5-3=2) they learn the three numbers as a family.  They know if they know any two of the numbers of that family, then they can recall the third number.  This is a good way to learn facts.  Many teachers prefer it, so we offer it as an option in Rocket Math.  The only research I have seen on this showed that learning operations separately, first all addition, then all subtraction, was a bit more efficient than learning through fact families.  But there may be a benefit from learning in fact families that makes the fact that it is slower worthwhile.  That’s an open question.  Would make a great master’s study–especially since Rocket Math has both fact families and single operations available.  We have it in the Worksheet Program and the Online Game, so it would be easy to compare and students could be randomly assigned to the condition.