Ratios and Proportional Relationships
How much for one?
Find what one thing costs or weighs, then use it to work out any number of them.
Some questions look impossible until you ask a smaller one first. If 4 pens cost 60, working out the price of 7 pens seems hard — until you find what one pen costs. After that, any number of pens is one multiplication away.
The rule
Divide to get down to one, then multiply to get up to as many as you want. One is the stepping stone, and it is nearly always the quickest route.
Worked example
5 identical bags of rice weigh 20 pounds altogether. What do 3 bags weigh?
Find one bag first: 20 ÷ 5 = 4.
Dividing by how many you have is what takes you down to a single one.
Try it together
6 tickets cost $90. Let us work out what 4 tickets cost.
Down to one first, then back up. Give just the numbers.
1.What does one ticket cost?
Have a go
Have a go on your own: 3 bags of flour weigh 12 pounds. What do 5 bags weigh, in pounds? Give just the number.
Ready to practice?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.