Can you ever use a calculator to determine if a number is irrational or rational?

And explain how you got it so i can understand future problems : 3

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81

Long division setup showing an incomplete calculation. 12 is in the divisor, 6839 is in the dividend, and 5 hundreds and 6 tens is written in the quotient. 6000 is subtracted from 6839 to give 839. an unknown value represented by a box is being subtracted from 839. what number should be placed in the box to complete the division calculation?