One group at a time

Primary 4 Four Operations of Whole Numbers · Lesson video · 2 min 36 s

P4 grouping problems: work with repeating bundles, distinguish paid items from free items and connect equal gaps with the objects at their ends.

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Questions in this lesson

  1. 0:06 Example 1: Ravi buys some pens and files. A pen costs $2 and a file costs $5. He buys 3 times as…
  2. 1:16 Example 2: A bakery gives 1 free bun for every 4 buns bought. Ali takes home 35 buns, all in full…
Transcript

Ravi buys some pens and files. A pen costs 2 dollars and a file costs 5 dollars. He buys 3 times as many pens as files. He pays 66 dollars altogether. How many pens does he buy? Try it first. Pause if you like. For every file, Ravi buys 3 pens. So put 3 pens and 1 file together in one group. 3 pens cost 3 times 2, which is 6 dollars. Add the file. One group costs 6 plus 5, which is 11 dollars. Ravi pays 66 dollars. 66 divided by 11 is 6, so there are 6 groups. Each group has 3 pens. 6 times 3 is 18. So Ravi buys 18 pens.

A bakery gives 1 free bun for every 4 buns bought. Ali takes home 35 buns, all in full offer groups. Each bun costs 2 dollars. How much does Ali pay? Try it first. Pause if you like. For every 4 buns Ali pays for, he gets 1 more bun free. So one offer group has 4 plus 1, which is 5 buns. Ali takes home 35 buns. 35 divided by 5 is 7, so there are 7 offer groups. In every group, Ali pays for 4 buns. 7 times 4 is 28 buns. Each bun costs 2 dollars. 28 times 2 is 56. So Ali pays 56 dollars altogether. Find what one group holds or costs, then count how many groups there are.