140 stickers are in 3 packets.
The second packet has 8 times as many stickers as the third packet.
The first packet is 10 less than the third packet.
How many less stickers are there in the third packet and the first packet than in the second packet?
Choose the packet with the least stickers to be 1 u.

Number of stickers in the first packet = 1 u
Number of stickers in the third packet = 1 u + 10
Number of stickers in the second packet = 8 x (1 u + 10) = 8 u + 80

Total number of stickers
= 8 u + 80 + 1 u + 10 + 1 u
= 8 u + 1 u + 1 u + 80 + 10
= 10 u + 90

10 u + 90 = 140
10 u = 140 - 90
10 u = 50

1 u = 50 ÷ 10 = 5

Number of less stickers in the third packet and first packet than the second packet
= (8 u + 80) - (1 u + 10 + 1 u)
= (8 u + 80) - (2 u + 10)
= 8 u - 2 u  + 80 - 10
= 6 u + 70
= 6 x 5 + 70
= 30 + 70
= 100

Answer(s): 100