KanjiJLPT N4
Number

number, strength, fate, law, figures

Mnemonic

A woman scatters rice across the floor and orders a ninja to count every last grain. The ninja's hands blur as he sorts them into neat piles, whispering each number aloud — it was his destiny to complete this tedious mission.
Additional thoughts
Picture the ninja crouching over thousands of rice grains, fingers flying, the woman standing behind him with arms crossed. The idea of destiny ties into the kanji's secondary meaning of fate — his number was up the moment she asked.
Quick recall
A woman makes a ninja count every grain of rice, whispering each number like a fate he can't escape.

Details

The keyword for 数 is number. This kanji refers to the concept of counting, numbers, or numerical quantity. It encompasses the act of enumerating or reckoning things, as well as the abstract idea of a figure or amount. It can also carry the sense of fate or destiny, as in something that is "numbered" or predetermined.
On'yomi
すう、す、さく、そく、しゅ
Kun'yomi
かず、かぞ.える、しばしば、せ.める、わずらわ.しい