Cogito
Grade 4 Math · Chapter 3 · Lesson 3
What the Remainder Means
One division, three different right answers.
10 problems · about 15 minutes · 4.OA.A.3
What this lesson teaches
The child interprets a remainder according to the situation, rounding up, down, or reporting it.
- One division can give three different right answers.
- Sometimes round up, sometimes ignore it, sometimes report it.
- The question decides, not the arithmetic.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
2 problemsReview — Remainders: 45 ÷ 7. What is the remainder?
Answer 3
Why 45 ÷ 7 = 6 remainder 3.
Review — Dividing by One Digit: 738 ÷ 6 = ?
Answer 123
Why 738 ÷ 6 = 123.
Warm Up
Straightforward practice. Get the method working first.
3 problems35 children, buses hold 9. How many buses?
Answer 4
Why Round up to 4 buses.
What decides what to do with a remainder?
Answer The question being asked.
Why The situation decides whether to round up, ignore it, or report it.
20 children, cars hold 6. How many cars are needed?
Answer 4
Why Round up.
Build It Up
The same ideas with more to keep track of.
1 problem20 pounds, items cost 6. How many can you buy?
Answer 3
Why Ignore the remainder.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
4 problems20 shared among 6. How many are left over?
Answer 2
Why 20 − 18.
The Minibuses: 30 children travel in minibuses holding 8 each. How many minibuses are needed?
Answer 4 minibuses
Why Round up to 4 minibuses.
The Shopping: 30 pounds buys notebooks costing 8 pounds. How many can you buy?
Answer 3 notebooks
Why Ignore the remainder. You can buy 3.
The Leftover: 30 sweets shared among 8 children. How many are left over?
Answer 6 left over
Why Here the remainder is the answer: 6.