Two decimal numbers have a difference of 0.7 And and a sum of 1. What are the numbers?

Use an equation for questions like these:

I'll use x and y as the unknown numbers

x-y=0.7

x+y=1

Just choose either x or y to solve for

y=x-0.7

y=-x+1

Then since since they're both equal to y then they can equal each other

x-0.7=-x+1

2x-0.7=1

2x=1.7

x=0.85

Then just grab one of the equations and use it to find y

0.85+y=1

y=0.15

So the two numbers are 0.85 and 0.15

The two numbers are 0.85 and 0.15

if you add them together you get 1, 0.85+0.15=1

and if you subtract them you get 0.7, 0.85-0.15=0.7