I describe 5 Mental Math Strategies that students can use to help solve math equations.

1. Mental Math
Strategies
for Grade 3 Students
All photos Courtesy of
MS Clip Art
Roshel Salvador

2. What is Mental Math??

3. It’s the ability to solve math
equations in your head….

4. WITHOUT
using
paper OR a pencil!

5. With Mental Math
you can manipulate
(change) your
number to make an
easier equation.
What’s an equation???
It’s the number sentence.

6. Here are a few Mental Math
strategies:
• Count on
• Doubles
• Near Doubles
• Make a Friendly Number
• Front-End Adding or
Expanded Notation

7. Count On:
If one of the numbers being
added is a small number,
then just count on.

8. Count On:
7+3=
3 is a small number,
so just count on
to get your answer.

9. Count On:
RULE:
Usually, if one of the numbers
are from 1 to 5, you can just
count on.

10. Doubles:
Knowing your doubles
can help you solve
equations quickly!

11. Doubles:
Doubles are when you take a number and
add it to itself.
Eg. 2+2=
9+9=
15+15=
25+25=
You double the number.

12. Near Doubles:
Knowing your doubles
helps with the Near
Doubles strategy

13. Near Doubles:
Near Doubles almost looks like a
double, but it is off by 1,2,3 or 4
Near Double
2 + 2+1
Doubles
Doubles

14. Near Doubles:
Examples of other near doubles:
11+13= 5+8=
11 + 11+2= 5 + 5+3

15. Near Doubles:
You can even use subtraction for
near doubles.
11+13= 5+8=
13-2 + 13 8-3 + 8
8+8 - 3
13+13 - 2

16. Make a Friendly Number:
What is a
friendly number???

17. Make a Friendly Number:
A friendly number is a
number that ends with a
“0”.
Numbers with a “0” in the
ones spot are easier to
add with

18. Make a Friendly Number:
For example,
to make 28 a friendly number,
I can add 2 to it
to make it 30

19. Make a Friendly Number:
More examples:
• Add 5 to 35, to make 40
• Subtract 2 from 22 to make 20

20. Make a Friendly Number:
This is how it helps:
9 + 4=
If I make 9 into a 10,
10 + 3=
it is easier to solve
because I’m working with a
friendly number.

21. Make a Friendly Number:
BUT….
Notice how I changed the equation to
10 + 3, NOT 10 + 4
I had to manipulate the equation.
Otherwise, I’m just make a new and different
equation that won’t give the same answer

22. Make a Friendly Number:
In adding, it is called “give and take”.
If you give to one side, you have to
take from the other side.
9 + 4= 13
(give 1) +1 -1 (take 1)
10 + 3= 13 New equation

23. Make a Friendly Number:
In subtracting, it is called
“give/give” or “take/take”.
If you give to one side, you have to
give to the other side.
If you take from one side, you have
to take from the other side.

24. Make a Friendly Number:
Some examples of “give/give” and
“take/take”:
9 – 4= 5
(give 1) +1 +1 (give 1)
10 – 5= 5 New equation
11 – 4= 7
(take 1) -1 -1 (take 1)
10 – 3= 7 New equation

25. Make a Friendly Number:
When you:
• “give & take” adding
• “give/give”  subtracting
• “take/take”  subtracting
You are compensating!

26. Front-End Adding
When you front-end add you
use expanded notation or
your place values.

27. Front-End Adding
Expanded Notation is breaking your
number into ones, tens and hundreds
Eg. 58 42
5 tens, 8 ones 4 tens, 2 ones
50 + 8 40 + 2

28. Front-End Adding
• Front-end adding is when you start adding
from the left and move to the right
Eg. 34 + 45
- start with the tens: 30 + 40 = 70
- now the ones: 4 + 5 = 9
Now you`re working with a friendly number
70 + 9 = 79

29. Let’s Review the Mental Math
Strategies
• Count on
• Doubles
• Near Doubles
• Make a Friendly Number
• Front-End Adding or
Expanded Notation