Ratio recipe: keep the same taste

Grade 6 mathematics · 15 minutes · Ratios

Use equivalent ratios to scale a recipe and explain why adding equal amounts changes the ratio.

Classroom activity

A fruit drink uses 2 cups of concentrate for every 3 cups of water.

1. Draw two groups of 2 concentrate cups and 3 water cups. Record the total amounts.
2. Complete a table for 1, 2, 3, and 4 batches. Label both quantities.
3. A club needs 15 cups of drink. How much of each ingredient should it use? Explain.
4. Sam adds 2 cups to each amount in the original recipe. Is the taste unchanged? Compare the ratios with a drawing or equivalent fractions.

Work independently for 3 minutes, compare with a partner for 5 minutes, then discuss the two methods.

Check understanding

A recipe uses 3 cups of oats for every 2 cups of seeds. How many cups of seeds go with 12 cups of oats? Explain the scale factor.

Teacher guide and answers

The table is (2,3), (4,6), (6,9), (8,12). For 15 cups total, use 6 concentrate and 9 water. Adding 2 gives 4:5, which differs from 2:3. The check answer is 8 cups of seeds, using a factor of 4. Listen for scaling both quantities rather than adding the same amount. If needed, return to equal-sized batches; extend by finding amounts for 7.5 cups total.

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Grade 6 topic reference. Confirm your adopted standards; topic guidance does not certify alignment.