Mental Math
12 × 8
What is 96?
Solve: 3x = 27
What is x = 9?
A triangle’s angles add up to this number.
What is 180 degrees?
2, 4, 6, 8, ___
What is 10?
I am an odd number. Take away one letter and I become even. What number am I?
What is seven?
25 × 16
What is 400?
Solve: 5x − 10 = 15
What is x = 5?
A rectangle has length 12 and width 5. Find the area.
What is 60?
3, 6, 12, 24, ___
What is 48?
If two’s company and three’s a crowd, what are four and five?
What is nine?
48 ÷ 6 × 5
What is 40?
Solve: 2x + 7 = 19
What is x = 6?
A square has side length 9. Find the perimeter.
What is 36?
5, 9, 13, 17, ___
What is 21?
I am a three-digit number.
The sum of my digits is 15.
All my digits are the same.
What number am I?
What is 555?
15² − 10²
What is 125?
Solve: 4(x − 3) = 20
What is x = 8?
Right triangle with legs 6 and 8. Find the hypotenuse.
a2+b2=c2
What is 10?
1, 4, 9, 16, ___
What is 25?
A farmer has 17 sheep.
All but 9 run away.
How many sheep are left?
What is 9?
99 × 99
What is 9801?
Solve: 3x + 2x − 5 = 20
What is x = 5?
A circle has radius 7. What is the diameter?
What is 14?
2, 3, 5, 8, 12, ___
What is 17?
A bat and a ball cost $1.10 total.
The bat costs $1 more than the ball.
How much does the ball cost?
What is 5 cents?
(The bat costs $1.05.)