Two Numbers with a Sum of 12 and a Difference of 8

Define variables:
Let x = larger number and y = smaller number
Resulting system of equations:
x + y = Sum
x − y = Difference
Solve the system of equations for x (larger number):
x =  

Sum + Difference/2

Find x by substituting given Sum and Difference into equation for x and simplify:
x =  
x =  
x =  10
Solve the system of equations for y (smaller number):
y =  

Sum − Difference/2

Find y by substituting given Sum and Difference into equation for y and simplify:
y =  
y =  
y =  2
Therefore, the two Numbers are 10 and 2
Check Sum of the two Numbers:

	1	0
		2
	1	2

10 + 2 = 12 ✓
Check Difference between the two Numbers:

	0	10
	1	0
−		2
		8

10 − 2 = 8 ✓