Missing Numbers in Times and Divide
Find unknown values in numerical equations involving multiplication and division using the properties of numbers and operations.
Read this first
Use the inverse to find what is missing. Then check by putting it back in.
4 times something makes 20. The array shows the answer is 5.
Words you need
- Unknown
- The number you are looking for.
- Inverse
- The operation that undoes it.
- Check
- Put your answer back in to test it.
Worked example
e.g. Find the missing number: 4 x ? = 20
- Read it out. 4 times something makes 20.
- Use the inverse. Divide 20 by 4.
- 20 divided by 4 is 5.
- Check it. 4 x 5 = 20. Correct.
Always check. It takes two seconds and catches mistakes.
Practice
The pictures fade as you go. By the last few you are on your own.
1Find the missing number: 3 x ? = 18with a picture
Answer6.
2Find the missing number: ? x 5 = 35with a picture
Answer7.
3Find the missing number: 24 / ? = 6with a hint
Need a hint?
6 times what makes 24?
Answer4.
4Find the missing number: ? / 3 = 9with a hint
Need a hint?
Multiply to undo the divide.
Answer27.
5Find the missing number: 8 x ? = 56on your own
Answer7.
6Find the missing number: 45 / ? = 9on your own
Answer5.
7Check this: 6 x 7 = 42. Then 42 / 6 = 8. Is that right?on your own
AnswerNo. 42 / 6 = 7.
Think about it
1
Why does the inverse help?
One good answerIt undoes the step, so the unknown is left alone.
2
What does the equals sign promise?
One good answerBoth sides are worth exactly the same.
Common mistakes
Guessing and moving on.
Always put your answer back in to check.
Using the same operation instead of the inverse.
To undo a times, you divide.