Proportion and the unitary method
Use a proportion table to find a missing amount: first the amount for one, then for any number. Inverse proportion comes last.
- UK: Year 5
- France: grade 4
- Germany: grade 5
- Iran: grade 5
- Afghanistan: grade 6
- Syria: grade 6
- Palestine: grade 6
- Ukraine: grade 6
- Russia: grade 6
Guide
This studio practises the "make a table" strategy for proportion problems, using the proportion table of the Iranian Year 5–6 books. Some cells are given by the problem, some your child fills in, and some columns work themselves out (such as "drink" or "workers × days").
Two equal ratios make a proportion. In the first mission (milk and calcium, from the Iranian Year 5 lesson) the common mistake is to add instead of multiply: "15 to 20 is 5 more, so 18 + 5". In a proportion both amounts are multiplied by the same number.
The unitary method: first find the amount for one (the price of one pencil), then for any number. The third mission comes from the Iranian Year 6 book: a drink made with 1 cup of honey to 3 cups of water, with a "drink" column that adds itself up and checks the answer.
The last mission is inverse proportion (Afghan Grade 6): the more workers, the fewer days. The "workers × days" column shows what stays the same.