13 + 21 = 13- -21
The minus sign and negative cancel each other out.
Place values:
As each is in a different place value, when we add them neither will affect the other, meaning:

Answer: B 4.39
Answer:
Jasmine ran last week 37.2 miles
Step-by-step explanation:
Let
x ----> number of miles Rob ran last week
y ----> number of miles Jasmine ran last week
we know that
x=y-27.2 ----> equation A
x=10 ----> equation B
Substitute equation B in equation A and solve for y
10=y-27.2
y=10+27.2
y=37.2 miles