# Maths Mate Sheet 2 Question 23 (Term 4 2014)

Prediction: I predict this problem will be about working backwards.

Read: I think of a number , add 9 and then multiply it by 3. If the result is 30, what was the original number?

Clarification: None needed.

The Big Question: What was the original number?

Mathematician’s Toolbox: Work backwards/Have I seen a similar problem?

Solving: First I worked backwards from 30. I used division because multiplication is division backwards. So I did 30 divided 3 which is 10. After that I subtracted 9 because addition is the inverse operation of subtraction. So I subtracted 9 and I got the result of 1.

Conclusion: So the answer was 1.