Cogito
Grade 3 Math · Chapter 3 · Lesson 3
Multiplying by 7
Fives plus twos.
10 problems · about 13 minutes · 3.OA.C.7, 3.OA.B.5
What this lesson teaches
The child recalls the 7 times table, building it from fives and twos.
- Sevens are the hardest table.
- Split a seven into a five and a two.
- Add the two products.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
2 problemsReview — Multiplying by 6: 9 × 6 = ?
Answer 54
Why 9 × 6 = 54.
Review — Breaking an Array Apart: 7 × 8 = ?
Answer 56
Why 40 + 16 = 56.
Warm Up
Straightforward practice. Get the method working first.
4 problems8 × 7 = ?
Answer 56
Why 8 × 7 = 56.
How can you split a seven?
Answer Into a five and a two.
Why Splitting into five and two uses two tables you know well.
4 × 7 = ?
Answer 28
Why 20 + 8.
7 × 7 = ?
Answer 49
Why 35 + 14.
Build It Up
The same ideas with more to keep track of.
2 problems9 × 7 = ?
Answer 63
Why 45 + 18.
56 ÷ 7 = ?
Answer 8
Why What times 7 makes 56?
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Weeks: How many days are in 6 weeks?
Answer 42 days
Why 6 × 7 = 42 days.
More Weeks: How many days are in 9 weeks?
Answer 63 days
Why 9 × 7 = 63 days.