Question

What is the final answer of 2.169/0.68?

Answer 1

`2.169/0.68=3.2`, with two significant digits.

Explanation:

This is a prolem of sinificant digits. Remember the following rules for arithmetic with significant digits:

1) When adding or subtracting, round to the smallest power of 10 where both numbers have significant digits. Thus `2.169-0.68=0.49`, not `0.489`, because `2.169` has a significant digit in the thousandth place but `0.68` has a significant digit only in the hundredths place.

2) When multiplying or dividing, roundbto the lowest number of significant digits of the two numbers. Thus `2.169/0.68=3.2` because `2.169` has four significant digits but `0.68` has only two.

If we meant for `0.68` to be accurate to four significant digits we would have rendered it as `0.6800`, counting the "extra zeroes after the decimal point as additional significant digits.