Pete thinks of a number. He squares it, then takes away 5, next multiplies it by 4, takes away 7, divides it by 3 and finally adds 6. His answer is 45. What number did he start with?

The answer you is looking for is 6.

This is the equation this problem would make:

?^2-5*4-7/3+6=45

Since you know the answer, you can find a missing number by choosing the opposite symbol:

?/6+5/4+7*3-6=45

This is how you work backwards with this problem:

45-6 = 39

39*3 = 117

117+7 = 124

124/4 = 31

31+5 = 36

36/6 = 6

When you square root, you are taking the two numbers and multiplying then together. These numbers need to be the same, though. For example, 6*6=36, 6 squared=36.

If you put 6 where the? is, your answer will be 45:

6^2-5*4-7/3+6=45