Times-table recall (to 20x20) sprint

Aim for instant recall of every fact up to \(12 \times 12\). Then build the teens fast with a few tricks.

• Teens: split off the 10. \(17 \times 7 = 70 + 49 = 119\). \(13 \times 8 = 80 + 24 = 104\).
• Times 9: times 10, then take one copy away. \(19 \times 9 = 190 - 19 = 171\).
• Times 4 and 8: keep doubling. \(16 \times 4\): \(32\), then \(64\).
• Times 5: half of times 10. \(17 \times 5 = 170 \div 2 = 85\).
• Times 11 (two-digit number): put the digit sum in the middle. \(11 \times 14 = 154\). If the sum is 10 or more, carry the 1: \(11 \times 68 = 748\).

Facts students mix up most: \(6 \times 7 = 42\), \(6 \times 8 = 48\), \(7 \times 7 = 49\), \(7 \times 8 = 56\), \(8 \times 9 = 72\).

Quick checks: an even number times anything is even, and the digits of any multiple of 9 add up to a multiple of 9 (\(171\): \(1 + 7 + 1 = 9\)).