Cogito
Grade 3 Math · Chapter 3 · Lesson 8
Patterns in the Times Tables
The tables are full of patterns, and each one has a reason.
10 problems · about 13 minutes · 3.OA.D.9
What this lesson teaches
The child identifies patterns in the multiplication table and explains them using properties.
- An even factor always makes an even product.
- Only odd times odd gives an odd product.
- A pattern is worth more once you can say why.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — Missing Factors and Divisors: 7 × ? = 63
Answer 9
Why 7 × 9 = 63.
Review — Multiplying by Multiples of Ten: 7 × 40 = ?
Answer 280
Why 7 × 4 = 28, so 7 × 40 = 280.
Review — The Associative Property: 2 × 5 × 6 = ?
Answer 60
Why Grouping the 2 and 5 first makes it 10 × 6.
Warm Up
Straightforward practice. Get the method working first.
3 problemsIs 8 × 7 odd or even?
Answer Even
Why An even factor makes the product even.
When is a product odd?
Answer Only when both factors are odd.
Why One even factor is enough to make the product even.
Is 5 × 9 odd or even?
Answer Odd
Why Both factors are odd.
Build It Up
The same ideas with more to keep track of.
1 problemWhat is 7 × 7?
Answer 49
Why A square number.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
3 problemsIn the nine times table, the digits of each answer add to what?
Answer 9
Why Try 18, 36, 54.
Odd or Even: Is 7 × 6 odd or even?
Answer Even
Why An even factor always makes an even product.
The Square: What is 6 × 6?
Answer 36
Why 6 × 6 = 36, a square number.