Any even factor gives an even product
Anything times 2, 4, 6, 8, or 10 is even, because it is made of equal pairs.
Math · Grade 3 Math
Chapter 3: Building the Times Tables
The tables are full of patterns, and each one has a reason.
Read it, or press Listen and follow the words.
Anything times 2, 4, 6, 8, or 10 is even, because it is made of equal pairs.
3 × 5 = 15. Two odd factors are the only way to get an odd product.
1, 4, 9, 16, 25 sit on the diagonal. Each is a number times itself.
Spotting a pattern is good. Saying why it happens is better.
Every product in the 2, 4, 6, 8 and 10 tables is even, because each is a number of even-sized groups. The 5 table alternates 5 and 0. The 9 table has digits that always add to 9. Each pattern has a cause, and finding the cause is more valuable than memorising the pattern.
Run down the diagonal of a times table grid and you get 1, 4, 9, 16, 25, 36, 49, 64, 81, 100 — the square numbers. Their arrays are actual squares. The gaps between them go 3, 5, 7, 9, all the odd numbers in order, which is a striking pattern worth noticing.
Fold a times table grid along the square-number diagonal and every entry matches its partner, because 6 × 4 and 4 × 6 are equal. That symmetry is the commutative property made visible, and it is why the grid contains far fewer distinct facts than it has cells.
Tap and try it out.
| + | 0 | 1 | 2 | 3 | 4 | 5 |
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| 0 | ||||||
| 1 | ||||||
| 2 | ||||||
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| 5 |
Tap any square to see its number sentence.
4 × 4 = 16
4 rows of 4 makes 16.
One step at a time.
Leo notices every answer in the 4 times table is even.
He checks a few: 4, 8, 12, 16. All even.
Practice makes it stick.
Odd or Even
Problem 1 of 2
Is 7 × 6 odd or even?
The Square
Problem 2 of 2
What is 6 × 6?
1 of 3
Is 5 × 9 odd or even?
2 of 3
What is 7 × 7?
3 of 3
In the nine times table, the digits of each answer add to what?
Show what you know.
Question 1 of 2
Is 8 × 7 odd or even?
Question 2 of 2
When is a product odd?