Correct

倒读数

/ dǎo dúshù / 
Strokes

Example

As a Verb

count down

1
Wéi
为
hángtiānfēijī
航天飞机
de
的
fāshè
发射
kāishǐ
开始
dǎo
倒
dúshù
读数

begin the countdown for the launch of a space shuttle