I think of a number. I multiply it by 3 and then subtract 5. I get an answer of 16. What was the number I first thought of?

This question is asking us to work our way back and find the original number. We can refer to this number as 'x'. If we multiply x by 3 we get 3x. The next step is to subtract 5, so our equation now is 3x-5. We have been told that the answer is 16, so the equation that we have is: 3x-5=16. Now, to work out the original number we must isolate x on its own, which involves doing the reverse of the signs. First we add 5 on both sides to get 3x = 21. Since 3 is multiplied by x, to get x on its own we divide by 3 to get x = 21/3 which is 7. So the original number is 7. To check we have the right answer, we can insert our value into the equation we formed and see if the equation equals to 16. So, inserting 7 into 3x-5 = (3x7)-5 = 21-5 = 16. Since the equation does equal to 16, we know that 7 is the correct answer to this question.