Parent guide · Grade 3 Math · Unit 1

Lesson 1.2 Rounding to 10 and 100

Written for the parent. Read the Say this lines aloud as they are, or in your own words. Answers for you are marked Listen for.

At a glance

Time: 5 sessions of 25–30 minutes
Goal: Round to the nearest 10 and 100.
You need: Pencil and crayons
Print: Worksheet A · Worksheet B · the lesson page (it also has a short video (10:41))

Steps

Warm-up
Do this: Ask these out loud. Your child answers out loud; no paper needed.
- Ask: “7 + 4” Listen for: 11
- Ask: “5 + 2” Listen for: 7
- Ask: “7 + 5” Listen for: 12
Teach the new idea
Say this: “Find the two tens (or hundreds) the number is between, and see which is nearer.”
Say this: “Look at the digit to the right of the place you are rounding: 5 or more rounds up.”
Say this: “Round: find the nearest ten or hundred.”
Say this: “Halfway: the middle point; 5 rounds up.”
Show how
Show: Round 901 to the nearest 10.
Say this: “901 is between 900 and 910.”
Say this: “Look at the ones digit: 1. Less than 5, so round down.”
Say this: “901 rounds to 900.”
Answer: 900
Show: Round 773 to the nearest 100.
Say this: “773 is between 700 and 800.”
Say this: “Look at the tens digit: 7. 5 or more, so round up.”
Say this: “773 rounds to 800.”
Answer: 800
Practice together
Do this: Your child does these with you. Let them try first; help only after a real try.
Ask: Round 18 to the nearest 10.
Listen for: 20
If stuck: 18 is between 10 and 20.
Ask: Round 85 to the nearest 10.
Listen for: 90
If stuck: 85 is between 80 and 90.
Ask: Round 91 to the nearest 10.
Listen for: 90
If stuck: 91 is between 90 and 100.
7 more practice items on the lesson page, and on Worksheet A and Worksheet B.
Watch for
- Rounding 350 down to 300. Halfway rounds up.
Game: Round-Off
Draw a card with a 3-digit number. Both players say it rounded to the nearest 10 and the nearest 100. First correct answer scores.
Narration
Say this: “Tell me what you learned today. Show me with your hands or the counters if you like.”
Listen for: Round to the nearest 10 and 100.
Daily habit
Count by 10s and 100s across a thousand (980, 990, 1,000, 1,010). Addition facts drill twice a week.

Spread over the week

5 sessions of 25–30 minutes. Stop while it is still going well.

Session 1. Warm-up, then teach the new idea (steps 1 and 2).
Session 2. Warm-up again, then show how with the examples.
Session 3. Practice together, then play the game.
Session 4. More practice on the worksheet, and the daily habit.
Session 5. Quick check: narration and a few practice items. Move on when it is mostly right.