How to add 9.73 and 21.6

Question

What is the best way to describe how to add 9.73 and 21.6 

Answer 1

Here's one method.  It's how I add in my head:

 

9.73 + 21.6

= 9 + 0.73 + 21 + 0.60    (separate the decimals from the whole numbers)

= 9 + 21 + 0.73 + 0.60    (group the whole numbers and the decimals)

= 30 + 0.73 + 0.60          (add the whole numbers)

= 30 + 1.33                    (add the decimals)

= 31.33                          (add the decimal to the whole number)

Answer 2

  9.73

21.60 

31.33