9 mental math strategies: Tips and Tricks for students

Mental math is an important skill for students of all ages. Applying mental math strategies can help you work faster and more accurately without a calculator.

In this article, we will list 9 strategies that will help you improve your skills. We’ll also include some tips and tricks to make mental math easier and faster!

From my 14+ years of teaching experience, I have observed that there are many students in high school that rely heavily on their calculators instead of using these mental math strategies.

By applying these tips and tricks they can work faster and apply these strategies to other topics such as Algebra and multiplying fractions.

What are mental math strategies?

Mental math strategies are simply methods or techniques that you can use to do math more quickly and accurately using your brain. These strategies can be used for addition, subtraction, multiplication, division, and more!

Here are my favorite mental math strategies that you can use:

1. Bridge to ten

Bridge to ten is when we count on to the next 10 and then add what is left.

Having knowledge of ‘friends of ten‘ which is basically recalling number combinations that add to 10, is essential prior knowledge.

The Bridge to ten strategy is great for simple additions such as 8+6.

You can change this to 8+ 2 + 4.

It is also great for questions such as 47 + 8.

Which can be bridged to ten as follows: 47 + 3 + 5.

Number lines are a helpful tool for this strategy.

2. Commutative Property

This mental math strategy can be used with addition and multiplication. It states that you can change the order of the numbers being added or multiplied and get the same answer. For example, 2+3 = 3+2.

Let’s say you’re adding up a list of numbers:

Instead of starting from left to right, try grouping them using ‘friends of ten’.

So you can see the total is 20 + 30 + 4 = 54

This can help you keep track of the numbers more easily and calculate the addition faster using this mental math strategy.

3. Adding 9

This mental math strategy can be used for addition. To use this strategy, you simply need to add 10 and then subtract 1.

For example, let’s say you’re trying to add 56+9

You can add the numbers like this:

Then, it becomes much easier to calculate the addition mentally because it is very easy to add 10 to a number.

4. Near doubles

Near doubles strategy is when you double a number and then adjust.

This is great when adding two consecutive numbers.

For example 7 + 8 is the same as double 7 plus 1, which equals 15.

Or you can adjust by doubling the larger number and subtracting 1.

For example 14+15 is the same as double 15 minus 1 , which equals 29.

5. Compensation strategy

The compensation strategy uses rounding up or down to make it easier to calculate an addition mentally.

First you want to round the second number up to the closest ten.

Then you compensate by subracting.

For example 47+19

This works for subtraction too.

For example, 76- 29

6. Doubling and halving

I LOVE this strategy! It is genius.

Doubling and halving is a mental math strategy for multiplication.

It works by halving one number (the larger one works best) and doubling the other number.

For example 48 x 5

7. Distributive property

The distributive property states that when you are multiplying a number by a certain sum or difference, you can multiply the number by each term in the sum or difference and then add the products together.

For example:

10 x (24 + 16) = 10 x 24 + 10 x 16 = 240 + 160 =400

Algebraically the distributive law looks like this:

This is a great mental math strategy to use for something like 99x 4

8. Using landmark numbers

Landmark numbers, such as multiples of ten or a hundred, are familiar with students so they can be used as a mental math strategy when adding.

For example 97 + 68.

97 is so close to 100. So you could add 3 to 97 and then subtract 3 from 68.

9. Repeated doubling to multiply by 4 and 8

Students often know how to double or multiply by 2 but their number facts for the 4 and 8 times tables are often not as strong.

Repeated doubling is a mental math strategy to help with this.

To multiply a number by four, double it twice.

For example, 12 x 4

To multiply a number by 8, double it three times.

For example 25 x 8

Final thoughts and my experience of using mental math strategies in the classroom

There are many more mental math strategies that I use regularly. These are just a few that I teach my high school mathematics students in our numeracy support sessions.

In my experience students need to be reminded of these strategies and given opportunities to practice them regularly.

As you can see, using mental math strategies can help you work faster and more accurately without a calculator. Try out these strategies the next time you’re doing your math homework.

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