# 三下五除二

## ChineseEdit

three

under; next; lower; below; underneath; down(wards); to go down; latter
five

remove; do away with; wipe out; divide; except
two
(三下五除二)
Literally: “three, down five, take away two”.

### EtymologyEdit

Step 1 Step 2 Step 3

A mnemonic device to aid with adding 3 to 2, 3 and 4 in base 10 (also 7, 8 and 9 in base 16) on an abacus.

For example, to calculate ${\displaystyle 3+3}$ :

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.

### IdiomEdit

1. (figuratively) (doing things) in an instant; in the blink of an eye; quickly and easily