# Math: Elementary School: 1st and 2nd Grade Quiz - Using Facts to Solve Missing Number Problems (Questions)

This Math quiz is called 'Using Facts to Solve Missing Number Problems' and it has been written by teachers to help you if you are studying the subject at elementary school. Playing educational quizzes is a fun way to learn if you are in the 1st or 2nd grade - aged 6 to 8.

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Using facts to solve problems means understanding that subtraction is the inverse of addition, and vise versa. Therefore, if you know that 6 + 4 = 10, you could find the missing number in 10 - ? = 4 by using the same numbers.

This quiz will help your child to solve missing number problems by using number facts known to them.

Can you find the missing number?

1. Which fact would help you solve:
10 - ? = 4
 [ ] 8 + 2 = 10 [ ] 10 + 4 = 14 [ ] 4 + 6 = 10 [ ] 10 + 6 = 16
2. What is the missing number:
12 + ? = 20
 [ ] 18 [ ] 8 [ ] 22 [ ] 12
3. What is the missing number:
20 - ? = 7
 [ ] 70 [ ] 30 [ ] 3 [ ] 13
4. Which number is missing:
? + 5 = 20
 [ ] 50 [ ] 15 [ ] 5 [ ] 20
5. Which number is missing:
100 - ? = 20
 [ ] 12 [ ] 18 [ ] 20 [ ] 80
6. You could use 45 + 55 = 100 to help you solve:
 [ ] 100 - 5 [ ] 40 + 500 [ ] 100 - 20 [ ] 100 - 55
7. You could use 100 - 25 = 75 to help you solve:
 [ ] 25 + 75 [ ] 75 - 25 [ ] 75 - 100 [ ] 25 - 100
8. If 15 + 85 = 100 is true, which of the following is not true?
 [ ] 100 - 15 = 85 [ ] 100 - 85 = 100 [ ] 100 - 85 = 15 [ ] 85 + 15 = 100
9. If 95 + 5 = 100 is true, which of the following is not true?
 [ ] 95 + 95 = 100 [ ] 5 + 95 = 100 [ ] 100 - 95 = 5 [ ] 100 - 5 = 95
10. If 16 + 84 = 100 is true, which of the following is not true?
 [ ] 84 + 16 = 100 [ ] 100 - 84 = 16 [ ] 16 + 16 = 84 [ ] 100 - 16 = 84
Math: Elementary School: 1st and 2nd Grade Quiz - Using Facts to Solve Missing Number Problems (Answers)
1. Which fact would help you solve:
10 - ? = 4
 [ ] 8 + 2 = 10 [ ] 10 + 4 = 14 [x] 4 + 6 = 10 [ ] 10 + 6 = 16
If 4 + 6 = 10, then 10 - 6 = 4
2. What is the missing number:
12 + ? = 20
 [ ] 18 [x] 8 [ ] 22 [ ] 12
12 + 8 is a number pair, or bond, to 20
3. What is the missing number:
20 - ? = 7
 [ ] 70 [ ] 30 [ ] 3 [x] 13
If 7 + 13 = 20, then 20 - 13 = 7
4. Which number is missing:
? + 5 = 20
 [ ] 50 [x] 15 [ ] 5 [ ] 20
20 - 5 = 15, so 15 + 5 = 20
5. Which number is missing:
100 - ? = 20
 [ ] 12 [ ] 18 [ ] 20 [x] 80
20 + 80 = 100 so 100 - 80 = 20
6. You could use 45 + 55 = 100 to help you solve:
 [ ] 100 - 5 [ ] 40 + 500 [ ] 100 - 20 [x] 100 - 55
If 45 + 55 = 100, you could solve 100 - 55 = 45
7. You could use 100 - 25 = 75 to help you solve:
 [x] 25 + 75 [ ] 75 - 25 [ ] 75 - 100 [ ] 25 - 100
If you know that 100 - 25 = 75, then you could solve 25 + 75 = 100
8. If 15 + 85 = 100 is true, which of the following is not true?
 [ ] 100 - 15 = 85 [x] 100 - 85 = 100 [ ] 100 - 85 = 15 [ ] 85 + 15 = 100
100 - 85 = 15, not 100
9. If 95 + 5 = 100 is true, which of the following is not true?
 [x] 95 + 95 = 100 [ ] 5 + 95 = 100 [ ] 100 - 95 = 5 [ ] 100 - 5 = 95
The numbers in each calculation should always be 5, 95 and 100
10. If 16 + 84 = 100 is true, which of the following is not true?
 [ ] 84 + 16 = 100 [ ] 100 - 84 = 16 [x] 16 + 16 = 84 [ ] 100 - 16 = 84
16 + 16 = 32, not 100