Dividing by 8
for 4th grade

Dividing by 8

Work out the saving per item by dividing by 8

This topic focuses on the idea that you can often spend less per item if you buy a packet or so called mutli-pack. Manufacturers often accept less per item when selling more of a particular item. So, how can we work out how much is saved per item if we buy in bulk? What we need to do is work out the cost of each item in a pack, and compare that to the cost of an item bought singly.

The first question in this topic is as follows. If marbles cost 8 cents each, but a packet of 8 costs 56 cents, what is the amount you save PER ITEM by buying the packet.

So, if a packet of 8 marbles costs 56 cents then each marble in the packet costs:

56 ¢ ÷ 8 = 7 ¢ per marble

Which compares to 8 ¢ if we buy them individually.
So in this case the saving PER ITEM is:

8 ¢ - 7 ¢ = 1 ¢ per item

Note that you could also approach this problem through multiplication. Rather than dividing the packet price by 8, you could multiply the cost of the single item by 8. This would give you the difference in price for a packet. You would then need to divide to get the saving per item.

If you are finding this difficult, you might like to work through the lesson Introduction and Either / or activities before tackling the games.