Mental math strategies are techniques we use to perform mathematical calculations in our heads, without the need for written or external aids, like calculators. These strategies are particularly useful for solving arithmetic problems quickly and efficiently. Here are some common mental math strategies.
Counting on and counting back
Start with one number and count forward or backward by the other number to find the sum or difference. For example, to mentally add 7 + 3, start with 7 and count 3 more: 7, 8, 9, 10.
Making tens
When adding or subtracting numbers, try to make them into multiples of 10 or friendly numbers. For instance, to add 8 + 7, you can add 2 to 8 to make it 10, and then add 5 more to get 15.
Doubles and near doubles
Recognize and use the fact that doubles (e.g., 4 + 4) and near doubles (e.g., 4 + 5) have simple solutions. For near doubles, you can adjust the result by adding or subtracting 1.
Commutative property
Know that the order of addition doesn't change the result. For example, 5 + 3 is the same as 3 + 5.
Splitting numbers
Break down numbers into smaller, more manageable parts. For example, to add 48 + 36, you can split 36 into 30 + 6 and add 48 + 30 first and then add the remaining 6.
Subtracting to find the difference
When subtracting, think about how much needs to be subtracted to reach the nearest multiple of 10. For example, to subtract 7 from 18, you can subtract 2 to get to 16 and then subtract 5 more.
Estimation
Use estimation to quickly get a rough idea of the answer before performing the exact calculation. This helps in quickly identifying unreasonable results.
Crossing out common digits
When adding multiple numbers, you can cross out common digits to simplify the calculation. For example, when adding 27 + 38 + 43, you can add 20 + 30 + 40 first and then add the remaining 7, 8, and 3.
Number patterns
Recognize and use number patterns and relationships to solve problems more easily. For example, knowing that every 10 numbers have the same digit in the units place (e.g., 12, 22, 32, 42) can help simplify calculations.
Mental math worksheets
If your kids need practice on mental math worksheets, we have some they can get started with.
Grade 1 mental addition
For students at the grade 1 level, we start with adding simple numbers. In this set of worksheets all sums are less than 10.
This set contains simple addition problems with sums up to 20.
Grade 2 mental addition
We have several sets of mental addition worksheets for grade 2 students. Some that include no regrouping, and others that include regrouping. A good starting point is this page.
Grade 2 mental subtraction
Our subtraction sentences worksheets are appropriate for students learning mental subtraction.
Grade 3-5 mental math worksheets
If you are looking for mental math worksheets for the higher grades, we have included those under the addition, subtraction, multiplication and division categories for each grade.
