lesson
Count every combination once
1 · Learn
If every main dish can pair with every side, multiply the numbers of choices. Four mains and three sides give twelve pairs. Make an organised list to check.
Integer scaling means making an amount a whole-number multiple of another. Four times a 125 ml portion is 500 ml. Multiplication can be one step in a larger problem.
2 · Worked example
If six notebooks cost £3 each and a folder costs £2, the total is 6 × £3 + £2 = £20, not 6 × £5.
3 · Your turn
There are five fillings and three breads. How many one-filling, one-bread sandwiches are possible?
Check your answer
15 combinations, provided every filling can pair with every bread.
4 · Apply your learning
List all combinations for two groups of invented choices and check the total by multiplication.
Adult guidance and safety
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