5 Mental Math Tricks That Never Fail (With Examples)
Five arithmetic shortcuts that will make Target — and everyday life — easier. Each one takes about a minute to learn and a lifetime to appreciate.
A little mental math goes a long way. Here are five reliable shortcuts worth internalizing — for daily life and for our Target number puzzle.
1. Multiply by 5 the easy way
Multiplying by 5 is the same as multiplying by 10 and halving. 84 × 5 = 840 / 2 = 420. Faster than the algorithm you learned in third grade.
2. Multiply any two-digit number by 11
Add the two digits and drop the sum in the middle. 45 × 11 = 4 (4+5) 5 = 495. When the sum is 10 or more, carry the 1.
3. Round and correct
Turn hard addition into easy addition plus a small correction. 197 + 348 → 200 + 348 − 3 = 545. Works for subtraction too.
4. Square any number ending in 5
Take the leading digit, multiply by (itself + 1), then append 25. 35² = 3×4 = 12, then 25 → 1225. 65² = 6×7 = 42, then 25 → 4225.
5. Halve, then halve
Dividing by 4 is halving twice. Dividing by 8 is halving three times. Chain them together for surprisingly fast division.
Put them to work
For daily practice, play Target — every board rewards a few of these shortcuts. For deeper strategy, see our Target tips post.
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