Parent guide · Grade 1 Math · Unit 2

Lesson 2.4 Adding Three Numbers

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

Warm-up
Do this: Ask these out loud. Your child answers out loud; no paper needed.
- Ask: “3 + 3” Listen for: 6
- Ask: “5 + 1” Listen for: 6
- Ask: “8 + 1” Listen for: 9
- Ask: “6 + 4” Listen for: 10
- Ask: “0 + 6” Listen for: 6
Teach the new idea
Say this: “We can add in any order. Look for two numbers that make ten, then add the third.”
Say this: “3 + 7 + 5: 3 + 7 = 10, 10 + 5 = 15.”
Say this: “Any order: we can add numbers in any order and get the same total.”
Show how
Show: 7 + 9 + 2 = ___
Say this: “7 + 9 = 16”
Say this: “16 + 2 = 18”
Answer: 18
Show: 4 + 2 + 4 = ___
Say this: “4 + 2 = 6”
Say this: “6 + 4 = 10”
Answer: 10
Practice together
Do this: Your child does these with you. Let them try first; help only after a real try.
Ask: 1 + 6 + 6 = ___
Listen for: 13
If stuck: 1 + 6 = 7
Ask: 6 + 5 + 2 = ___
Listen for: 13
If stuck: 6 + 5 = 11
Ask: 5 + 6 + 6 = ___
Listen for: 17
If stuck: 5 + 6 = 11
7 more practice items on the lesson page, and on Worksheet A and Worksheet B.
Watch for
- Losing track of which numbers have been added. Cross them out as you go.
Game: Doubles War
Each player turns a card 1–10 and says its double. The bigger double wins both cards.
Narration
Say this: “Tell me what you learned today. Show me with your hands or the counters if you like.”
Listen for: Add three numbers.; Look for a ten or a double first.
Daily habit
Recite the doubles (1 + 1 to 10 + 10) every day, then the make-ten pairs.

5 sessions of 20–25 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.