Mix red and blue scoops, build ratio tables and scale recipes up and down. Play, solve missions, crack puzzles and beat the clock.
Start here. A ratio compares two amounts. If a mix has 2 red scoops and 3 blue scoops, we say the ratio of red to blue is 2 : 3. It means "for every 2 red there are 3 blue". The order matters: blue to red would be 3 : 2.
Same mix, bigger batch. Double the recipe and you get 4 red and 6 blue. The numbers changed but the taste did not, so 2 : 3 and 4 : 6 are equivalent ratios. Multiply or divide both numbers by the same amount. A ratio table lists these batches in a row.
Unit rate. If 5 pens cost $10, one pen costs $10 ÷ 5 = $2. Finding the cost for 1 is called a unit rate, and it lets you find the cost of any number of pens.
Proportion. Two ratios that are equal make a proportion, like 2 : 3 = 8 : 12. You can find a missing number by asking what both numbers were multiplied by. Maps use this too: if 1 cm stands for 5 km, then 7 cm stand for 35 km.
Sharing in a ratio. To share 40 stickers in the ratio 3 : 5, add the parts: 3 + 5 = 8 parts. Each part is 40 ÷ 8 = 5, so the shares are 15 and 25.
Try this above. In Play, add 2 red and 3 blue. Now press +1 group and ×2 on the ratio table and tap a column to load that mix into the jar. Then change the mix to 4 red and 6 blue and see that the simplest form stays 2 : 3.
A ratio compares two amounts of the same kind of thing, written with a colon, like 2 : 3. Read it as "2 to 3".
No. 2 : 3 means 2 red for every 3 blue. 3 : 2 means 3 red for every 2 blue. That is a different mix, so the order always matters.
It is the smallest whole numbers that still give the same ratio. 6 : 9 can be divided by 3 on both sides to get 2 : 3. Nothing bigger than 1 divides both 2 and 3, so 2 : 3 is the simplest form.
"Just starting" is about reading ratios and doubling recipes. "I know the basics" adds ratio tables, scaling recipes and unit rates. "Challenge me" adds proportions, map scales, sharing in a ratio and comparing mixes.
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