Mental Math Problem Samples
Upper Elementary
1. Find the sum of 15 and 12 (27)
Divide by 9 (3)
Add 48 (51)
Multiply by 2 (102)
2. Find the number of inches in 3 feet (36)
Subtract 6 (30)
Divide by the number of sides on a triangle (10)
3. Find the number of inches in ½ of a foot (6)
Multiply by 13 (78)
Subtract 18 (60)
Divide by 12 (5)
4. Find the difference between 52 and 32 (20)
Double that (40)
Increase that number by 64 (104)
Decrease that number by 100 (4)
5. Find the product of 12 and 3 (36)
Add 52 (88)
Divide by 11 (8)
Find ¼ of that number (2)
6. Find ½ the number of sides on an octagon (4)
Multiply by the number of sides on a rectangle (16)
Cut that number in half (8)
7. Find the sum of ½ and ¼ (3/4)
Subtract that number from 1 (1/4)
Double that (1/2)
8. Find the quotient of 220 and 10 (22)
Round to the nearest 10 (20)
Multiply by 20 (400)
Round to the nearest 1000 (0)
9. Find the number of nickels to make $0.20 (4)
Multiply that number by $0.25 ($1.00)
Add $13.52 ($14.52)
Subtract $3.40 ($11.12)
10. Find the product of 15 and 8 (120)
Add the number of degrees in a circle (480)
Subtract the number of degrees in a right angle (390)
Strategy Talk: When students do not get the mental math problem correct, this is the perfect opportunity for strategy talk. Go through each step and have students say the answer for that step to determine where the mistake is happening. Then have students share how they calculated it mentally. You, as the teacher, should then go over a few of the strategies with the whole class (write and/or draw them on the board). The purpose is for students to find an efficient strategy that works for them.
G & M ynthia Lee