3 sentences

1. 所有这些数字都是估算。

   suǒ​yǒu zhè​xiē shù​zì dōu shì gū​suàn.

   All of these numbers are estimates.

   Source: CCMatrix

2. 让我们做一个粗略的估算。

   ràng wǒ​men zuò yī​ge cū​lüè de gū​suàn.

   Let's make a rough estimate.

   Source: CCMatrix

3. 科学家如何估算地球的年龄呢？

   kē​xué​jiā rú​hé gū​suàn dì​qiú de nián​líng ne?

   How do scientists estimate the age of the earth?

   Source: CCMatrix