Stuck? Start here. Read the steps, try the problem, then check your answer.
I can…
I can use a ratio table to find equivalent ratios.
Key words
Ratio table — A table of equal ratios that shows a pattern.
Equivalent ratio — Two ratios that mean the same thing, like 1:2 and 2:4.
Scale factor — The number you multiply both parts of a ratio by to get an equal ratio.
Pattern — A rule that numbers follow again and again.
Additive pattern — Adding the same amount to both parts of a ratio table to make new rows.
Steps
The pancake recipe is 2 cups of mix for every 3 cups of milk, so the ratio is 2:3.
To make 2 batches, my scale factor is 2.
I multiply both numbers by 2: 2 x 2 = 4 cups of mix, and 3 x 2 = 6 cups of milk.
Now my row is 4:6, which is the same ratio as 2:3.
I do NOT add 2 to each number; I multiply both by the same factor.
Try it
A salad dressing recipe uses 2 tablespoons of oil for every 5 tablespoons of vinegar. How many tablespoons of oil are needed for 20 tablespoons of vinegar?
Check your answer
8
Scale factor: 20 ÷ 5 = 4. Multiply oil by 4: 2 × 4 = 8 tablespoons of oil.
Sentence starter
I know ___ because ___.
Goal: I can explain my table using the words ratio table, equivalent ratio, scale factor, and pattern.