Useful Mental Multiplication Shortcuts

Shortcuts are useful when they come from arithmetic identities rather than memorized magic.

Multiply by 9

47×9 = 47×10−47 = 470−47 = 423.

Multiply by 11

For a two-digit number, 32×11 = 32×(10+1) = 320+32 = 352. Understanding the identity is safer than relying on a digit trick.

Multiply by 25

Because 25 = 100/4, 48×25 = 4800/4 = 1200.

Numbers near 100

97×6 = (100−3)×6 = 600−18 = 582.

Educational note: these techniques are practice methods, not medical or cognitive-performance claims.