expensive calculator

English as a Second Language English Vocabulary, Grammar and Idioms
1

[color=indigo]1) He was using his expensive calculator and I was using mine.
[color=blue]2) He was using his expensive shock-resistant calculator and I was using mine.
[color=red]3) He was using his expensive shock-resistant calculator and I was using my fragile one.

Can we tell if my calculator was expensive or not?

Gratefully,
Navi.

2

In 1 and 2, you were using a calculator as expensive or good as his.
In 3, his calculator was better than yours. (Here we can’t say yours was as expensive)