a good first step is to look at which number has more numbers to the left of the decimal
16.1 has 2
1.06 has 1
16.01 has 2
1.16 has 1
16.61 has 2
Since three of them have two numbers to the left, you want to see which number starting from the left is the bigger number.
16.1 is 1
16.01 is 1
16.61 is 1
Since they all have 1 as their biggest number to the left you go one place to the right and try again. They all share a 6 this time, so you go over the decimal and do the same. You find that
16.1 is 1
16.01 is 0
16.61 is 6
Since 6 is the biggest of these three numbers, 16.61 is the largest number
