Nowadays people have smart ones, but at one time it was cutting edge to have a tiny calculator on your what?\nOptions:\n- mobile phone\n- wristwatch\n- briefcase\n- office\n- desktop
Let’s work this out in a step by step way to be sure we have the right answer.
wristwatch
Wristwatch can have a calculator.

Wristwatch is a device.

Wristwatch is worn around the wrist.

.

The final answer: wristwatch