Write a number in each blank to make the statements true. six pencils are equal in value to two rulers. one ruler is equal in value to two erasers. twelve pencils are equal in value to erasers. two erasers are equal in value to pencils. one ruler and four erasers equal the value of pencils.

P=value of a pencil
r=value of a ruler
e=value of an eraser

6p=2r

r=2e

alrigty
we can divide the fist one by 2

3p=r
so
3p=r=2e

neato

12 pencils is equal to ? erasers
3p=2e
times both sides by 4
12p=8e
8 erasers

2 erasers are equal to ? pencils
3p=2e
3 pencils

1 ruler and 4 erasers are equal to ? pencils
3p=r=2e
r+4e=3p+2(2e)=3p+2(3p)=3p+6p=9p
9 pencils

Twelve pencils are equal in value to eight erasers
Two erasers are equal in value to three pencils
One ruler and four erasers are equal the  value of nine pencils