Find the Decimal Between 0.1 and 0.2: Inequality Problem

Fill in the missing number (?):

$0.1 < ? < 0.2$

In order to discover our number range, we will first add 0 to both numbers as follows:

$0.1=0.10$

$0.2=0.20$

This means our number will be in the range of 0.10 to 0.20.

The numbers that exist in this range are: $0.11,0.12,0.13,0.14,0.15,0.16,0.17,0.18,0.19$

Now if we look at the possible answers, we can see that 0.15 is within this range and therefore is the correct answer.