18 times table

The 18 times table up to 18 × 12

The 18 times table is 18, 36, 54, 72, 90, 108, 126, 144, 162, 180, 198, 216. It goes past the 12 × 12 multiplication chart, so most schools do not require it: the Common Core stops at one-digit facts and England at 12 × 12. It is the 9 times table doubled and shares the digit-sum check of the 9s, which makes it a good table for learning to check answers. The chart above has every fact, and "Hide answers" turns it into a quick self-check.

Multiplication by 18 as 20 − 2

18 is close to 20, so multiply by 20 and take away 2 groups: 18 × 4 = 80 − 8 = 72; 18 × 8 = 160 − 16 = 144. The second way is doubling, because 18 is double 9: 9 × 6 = 54, doubled is 108, so 18 × 6 = 108. The 10 + 8 split works as well: 18 × 3 = 30 + 24 = 54.

The nine inside the 18s

Add the digits of any answer from 18 × 1 to 18 × 10 and you get 9: 36 → 3 + 6 = 9, 126 → 1 + 2 + 6 = 9, 162 → 1 + 6 + 2 = 9. Every answer is also even. A golf course has 18 holes, so two rounds of golf are 18 × 2 = 36 holes.

18 times table games and worksheet

The trainer asks the 18 times table out of order with a keypad. The facts children mix up most are 18 × 7 = 126, 18 × 8 = 144 and 18 × 9 = 162 (136, 154 and 172 are the usual slips), so the game brings a missed fact back two or three questions later until it is right three times in a row. When the round feels easy, take the speed test and then the test for the diploma. The 18 times table worksheet prints 30 problems with the answer key on page 2, and the third sheet practices the trick.

A tip for parents

The digit-sum check is a good habit: if the digits of an answer do not add up to 9 (or 18), the answer is wrong. Children like catching their own mistakes this way. Ask the facts the other way round too: 7 × 18 is the same as 18 × 7.