三下五除二

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Mandarin[edit]

simpl. and trad.

Etymology[edit]

A mnemonic device to aid with abacus addition of numbers greater than five.

Literally: three, down five, take away two

  • Ex. 3+3=6
    1. Start with three beads on the bottom (each lower bead is equal to 1).
    2. Move one of the top beads down (each top bead is equal to 5).
    3. Take away two of the beads from the bottom.
    4. This leaves you with one top bead (5) and one bottom bead (1), for a total of 6.
Step 1 Step 2 Step 3
0 0 0
0
0 0
--------------- --------------- ---------------
0 0 0
0 0
0 0 0
0
0 0 0
0 0 0

Idiom[edit]

三下五除二 (traditional and simplified, Pinyin sān xià wǔ chú èr)

  1. in an instant
  2. in the blink of an eye