Fill in the blanks.
For (a) to (c), give the answers in units (Eg 1 u) or unit equations (Eg 1 u + 2).

Adam has some stickers.
He has 10 more green stickers than blue stickers.
He has 20 more red stickers than
the sum of  the number of green and blue stickers.

1. How many more red stickers than blue stickers are there?
2. How many less green stickers than red stickers are there?
3. How many green and red stickers are there?

(a)
Choose the smallest group to be 1 u.

Number of blue stickers = 1 u
Number of green stickers = 1 u + 10

Number of blue and green stickers
= 1 u + 1 u + 10
= 2 u + 10

Number of red stickers
= 2 u + 10 + 20
= 2 u + 30

Number of more red stickers than blue stickers
= (2 u + 30) - 1 u
= 2 u - 1 u + 30
= 1 u + 30

(b)
Number of less green stickers than red stickers
= (2 u + 30) - (1 u + 10)
= 2 u + 30 - 1 u - 10
= 2 u - 1 u + 30 - 10
= 1 u + 20

(c)
Number of green and red stickers
= 1 u + 10 + 2 u + 30
= 1 u + 2 u + 10 + 30
= 3 u + 40

Answer(s): (a) 1u + 30 ; (b) 1u + 20; (c) 3u + 40