A The sum of two numbers is 31 and their difference is 7 Wha

A. The sum of two numbers is 31, and their difference is 7. What are the two numbers?

B.Which is a better estimate for the volume of a can of beans?

-30 tablespoons

-30 pints

C. How many decades are in 8 centuries?

D. Subtract: 6 kg 21 g - 3 kg 693 g = How many killograms and how many grams?

let 2 number be x, y

sum of two numbers is 31, and their difference is 7

=>x+y =31, x-y =7

=>x+y +x-y=31+7

=>2x=38

=>x=38_/2

=>x=19

x+y =31 ,x=19

=>19+y =31

=>y=31-19

=>y=12

the two numbers are 12, 19

30 pints is a better estimate for the volume of a can of beans

1 decade =10 years , 1century =100 years

10 decades in 1 century

so 80 decades in 8 centuries

6kg 21 grams -3 kg 693 grams

=5kg (1000+21) grams -3 kg 693 grams

=5kg 1021 grams -3 kg 693 grams

=(5-3)kg +(1021-693) grams

=2kg 328 grams