Parent guide · Grade 1 Math · Unit 6

Lesson 6.3 Two-Digit + Tens

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 20–25 minutes
Goal: Add tens to a two-digit number.
You need: A few real coins
Craft sticks and rubber bands
Pencil and crayons
Print: Worksheet A · Worksheet B · the lesson page (it also has a short video (3:16))

Steps

Warm-up
Do this: Ask these out loud. Your child answers out loud; no paper needed.
- Ask: “2 + 1” Listen for: 3
- Ask: “8 + 3” Listen for: 11
- Ask: “6 + 4” Listen for: 10
- Ask: “6 + 7” Listen for: 13
- Ask: “3 + 9” Listen for: 12
Teach the new idea
Say this: “For 34 + 20, add the tens: 3 tens + 2 tens = 5 tens. The ones stay: 54.”
Say this: “Think: 34, 44, 54.”
Say this: “Tens: groups of ten.”
Show how
Show: 70 + 20 = ___
Say this: “Add the tens: 70 + 20 = 90”
Answer: 90
Show: There are 58 ducks on the pond and 30 more fly in. How many ducks are on the pond now?
$bar model$
Say this: “Unknown: the total.”
Say this: “Bar model: two parts, 58 and 30; the whole is unknown.”
Say this: “Equation: 58 + 30 = ?”
Say this: “58 + 30 = 88”
Say this: “Answer: There are 88 ducks now.”
Answer: 88 ducks. There are 88 ducks now.
Practice together
Do this: Your child does these with you. Let them try first; help only after a real try.
Ask: 15 + 50 = ___
Listen for: 65
If stuck: Add the tens: 15 + 50 = 65
Ask: 29 + 30 = ___
Listen for: 59
If stuck: Add the tens: 29 + 30 = 59
Ask: 35 + 40 = ___
Listen for: 75
If stuck: Add the tens: 35 + 40 = 75
7 more practice items on the lesson page, and on Worksheet A and Worksheet B.
Watch for
- Adding 2 to the ones instead of 20.
Game: Tens Shop
Price toys at 10¢, 20¢ … 90¢. Your child pays with dimes and says the total of two toys, then the change from $1.
Narration
Say this: “Tell me what you learned today. Show me with your hands or the counters if you like.”
Listen for: Add tens to a two-digit number.
Daily habit
Count by tens from any number: 3, 13, 23 … and back down.

Spread over the week

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.