Two numbers have a difference of 0.7 and a sum of 1.what are the numbers?

Hi there!

To solve this problem, we should first make two equations, and use those to solve using the system of equations. 

Let x equal the larger number, and let y equal the smaller number. 
x - y = 0.7
x + y = 1

Now, we can use substitution in the system of equations to solve.

x + y = 1
x = 1 - y

1 - y - y = 0.7
1 - 2y = 0.7
-2y = -0.3
2y = 0.3
y = 0.15

Now, we solve for x:
x + 0.15 = 1
x = 0.85

So, the two numbers are 0.15 and 0.85. 

Hope this helps!