3 sentences

1. 桌上的计算器是我的。

   zhuō shàng de jì​suàn​qì shì wǒ de.

   The calculator on the table is mine.

   Source: Tatoeba

2. 他在数学考试中被允许使用计算器。

   tā zài shù​xué kǎo​shì zhōng bèi yǔn​xǔ shǐ​yòng jì​suàn​qì.

   He was allowed to use a calculator in his math exam.

   Source: Dong Chinese Dictionary

3. 这道数学题很难，我需要用计算器来计算。

   zhè dào shù​xué tí hěn nán, wǒ xū​yào yòng jì​suàn​qì lái jì​suàn.

   This math problem is difficult, and I need a calculator to solve it.

   Source: Dong Chinese Dictionary