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 20 more red stickers than green stickers.
He has 50 more blue stickers than
the sum of  the number of red and green stickers.

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

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

Number of green stickers = 1 u
Number of red stickers = 1 u + 20

Number of green and red stickers
= 1 u + 1 u + 20
= 2 u + 20

Number of blue stickers
= 2 u + 20 + 50
= 2 u + 70

Number of more blue stickers than green stickers
= (2 u + 70) - 1 u
= 2 u - 1 u + 70
= 1 u + 70

(b)
Number of less red stickers than blue stickers
= (2 u + 70) - (1 u + 20)
= 2 u + 70 - 1 u - 20
= 2 u - 1 u + 70 - 20
= 1 u + 50

(c)
Number of red and blue stickers
= 1 u + 20 + 2 u + 70
= 1 u + 2 u + 20 + 70
= 3 u + 90

Answer(s): (a) 1u + 70 ; (b) 1u + 50; (c) 3u + 90