Question

Is 2.73234(34 repeating) rational or irrational?

Answer 1

It's rational because of the repeating digits.

We have

x = 2.732343434…

Then

1,000x = 2,732.343434…

and

100,000x = 273,234.343434…

Subtracting these makes the fractional part go away, leaving you with

100,000x - 1,000x = 273,234.343434… - 2,732.343434…

100,000x - 1,000x = 273,234 - 2,732

99,000x = 270,502

x = 270,502/99,000 = 135,251/49,500

which is clearly a rational number.