what numbers make 14 and when you subtract them make 6?

Question

I am 9 and i have gotten alot of "which numbers make this number but when you subtract make this number" questions.

Answer 1

The numbers are 10 and 4. 10+4 = 14 and 10-4 = 6.

The question is how do you figure that out?

The following may be a bit too advanced for you at 9 years old, but it may help you see how to solve these kind of problems.

If we let x and y represent the two numbers then we can write the following two equations:

x + y = 14

x - y = 6

To solve the above system of equations you will learn some day the elimination method. Basically "equals added to equals are equal". So we can add the two equations together which will "eliminate" the y variable.

When you add the two left hand sides you get (x+x) = 2x and y + (-y) = 0. That is you get this:

2x = 20

So x must be 10.But if x is 10, then 10 + y = 14, so y must be 4.

Of course you could try trial and error instead of using equations. Make a list of numbers that add to 14 and see if any of them have a difference of 6.

1 + 13

2 + 12

3 + 11

4 + 10 <- there is the combination that has a difference of 6.

5 + 9