Multiplication Tricks That Beat Memorizing 100 Facts
You don't need to separately memorize every times table fact. A handful of patterns cover almost all of them.
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The Finger Trick for 9s
- Hold up both hands, palms facing you, fingers spread.
- To find 9 × n, fold down finger number n (counting from the left).
- Fingers before the fold = tens digit. Fingers after the fold = ones digit.
9 = 10 − 1, so 9×n is always "n tens, minus n." The folded finger is quite literally subtracting one group of ten.
Multiply by 10, Then Cut in Half
- Multiply the number by 10 (add a zero).
- Divide that result by 2.
5 is exactly half of 10, so this always works and is often faster than recalling a memorized fact for bigger numbers.
Double, Double (and Double Again)
- For ×4: double the number, then double the result.
- For ×8: double three times total.
Since 4 = 2×2 and 8 = 2×2×2, repeated doubling is mathematically identical to multiplying by 4 or 8 — and doubling is one of the easiest mental operations.
Split Into Tens and Ones (Distribute)
- Break the two-digit number into tens and ones.
- Multiply each part separately, then add.
This is the mental-math version of the box method — it works for any numbers, not just ones with a special pattern.
The 11 Trick: Split and Slide
- Take the two digits of the number apart.
- Add them together, and slide that sum between the original two digits.
- If the sum is 10 or more, carry the 1 into the first digit.
It's a fun, fast party trick — and understanding why it works (it comes from distributing ×10 and ×1) is a great intro to the box method above.
What it looks like: Using the 11s trick (split and slide) on a number like 11 × 68 and writing 6\|14\|8 = "6148" without carrying the extra ten.
Why it happens: The carrying step only comes up when the two digits add to 10 or more, so it's easy to forget it exists until a problem needs it.
The fix: Always add the two digits first and check: is it 10 or more? If yes, carry the 1 into the first digit before writing the final answer.
Where this shows up outside school
Doubling a recipe (×2, ×4), calculating the total cost of 8 identical items, or quickly estimating "about how many minutes in 9 hours" (9×60) all lean on these exact shortcuts instead of a memorized 12×12 grid.