problem solving: profit and enough information
Find a shopkeeper's profit with a table, and decide which numbers a problem needs, which it does not, or when one is missing.
- Iran: grade 3
Guide
This studio joins two lessons: the pattern lesson in the Iranian Grade 3 book (a shopkeeper's profit on sweets) and "solve it if the information is enough" in Grade 1.
Profit is the selling price minus the buying price. If a shopkeeper buys each sweet for 450 and sells it for 500, each sweet earns 50. The table grows by the same amount each time: a pattern.
Some problems have numbers you do not need. In others a number you do need is missing and the problem cannot be solved.