The 5-6-7-8 Trick

The fact people stumble on most is 7 × 8. Here is the cure: write the answer and the question side by side and you get 5, 6, 7, 8 in order.

56 = 7 × 8.

Four numbers in a neat run, no gaps. Once you see that consecutive line, this fact stops being the hard one and becomes one of the easiest to recall.

For the upper end of the table, work down from 7 × 10 = 70. Each step back is one seven.

Need 7 × 9? Subtract one seven: 70 − 7 = 63. Need 7 × 8? Subtract two sevens: 70 − 14 = 56. Need 7 × 7? Three sevens back: 70 − 21 = 49.

The high products you fear most are the closest to the 70 anchor, so they take the fewest steps. Counting down from 70 beats memorizing them cold.