三下五除二。(Sān xià wǔ chú èr.)to do things simply and quickly.

Explanation

“三下五除二”原是珠算加法的一句口诀,也说“三下五去二”，由于这个口诀和动作非常简洁，后用来比喻做事或动作干脆利索。
“三下五除二” is a pithy formula of addition in calculation with an abacus. People also say “三下五去二(Sān xià wǔ qù ér)”. It metaphorically means to do things simply and quickly.
Words:

复杂fùzá:complicated;
好吃hǎochī:delicious.

Sentences

1、Jiǎ: Zhè tài fùzá le.
甲：这太复杂了！
A: This is too complicated.

Yǐ: Qǐng Lǐ Míng bāngmáng ba, tā sān xià wǔ chú èr jiù néng zhěnglǐ hǎo.
乙：请李明帮忙吧，他三下五除二就能整理好。
B: You can ask Li Ming for help. He can simplify it quickly.

2、Jiǎ: Zhè dào cài zhēn hǎochī, dàjiā sān xià wǔ chú èr jiù dōu chī guāng le.
甲：这道菜真好吃，大家三下五除二就都吃光了。
A: This dish is so delicious that we eat it up in seconds.

Yǐ: Wǒ zài qù zuò yí gè ba.
乙：我再去做一个吧。
B: I am going to make one more.