Parent guide · Grade 2 Math · Unit 3

Lesson 3.3 The Written Method

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 two-digit numbers with the standard algorithm.
You need: Dice
Pencil and crayons
Print: Worksheet A · Worksheet B · the lesson page (it also has a short video (6:29))

Steps

Warm-up
Do this: Ask these out loud. Your child answers out loud; no paper needed.
- Ask: “38 + 20” Listen for: 58
- Ask: “19 + 40” Listen for: 59
- Ask: “44 + 30” Listen for: 74
- Ask: “27 + 60” Listen for: 87
- Ask: “17 + 70” Listen for: 87
Teach the new idea
Say this: “Line up the digits by place. Add the ones first, regroup if needed, then add the tens.”
Say this: “Write the regrouped 1 at the top of the tens column so you remember to add it.”
Say this: “Algorithm: a step-by-step method that always works.”
Show how
Show: 80 + 44 = ___
Say this: “Ones: 0 + 4 = 4. Write 4.”
Say this: “Tens: 8 + 4 = 12. Write 12.”
Say this: “80 + 44 = 124”
Answer: 124
Show: The oak is 78 feet tall. The apple tree is 73 feet tall. How much taller is the oak?
$comparison bar model$
Say this: “Unknown: the difference.”
Say this: “Bar model: a long bar of 78 and a short bar of 73; the difference is unknown.”
Say this: “Equation: 78 − 73 = ?”
Say this: “78 − 73 = 5”
Say this: “Answer: The oak is 5 feet taller.”
Answer: 5 feet. The oak is 5 feet taller.
Practice together
Do this: Your child does these with you. Let them try first; help only after a real try.
Ask: 27 + 57 = ___
Listen for: 84
If stuck: Ones: 7 + 7 = 14. Write 4 and regroup 1 to the tens.
Ask: 18 + 31 = ___
Listen for: 49
If stuck: Ones: 8 + 1 = 9. Write 9.
Ask: 49 + 17 = ___
Listen for: 66
If stuck: Ones: 9 + 7 = 16. Write 6 and regroup 1 to the tens.
7 more practice items on the lesson page, and on Worksheet A and Worksheet B.
Watch for
- Starting with the tens. Always start with the ones.
Game: Race to 100
Roll two dice, make a two-digit number (like 3 and 5 make 35 or 53), and add it to your total. First to reach exactly 100 or more wins.
Narration
Say this: “Tell me what you learned today. Show me with your hands or the counters if you like.”
Listen for: Add two-digit numbers with the standard algorithm.
Daily habit
One-minute addition drill on Fridays. Mental math: add 10 or 20 to any two-digit number.

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.