How do you subtract #8.47- 5.079#?

1 Answer
Mar 18, 2017

I got #3.391#

Explanation:

Ok, you could use a calculator but this is not fun.
We can use our good rules to subtract numbers in columns paying attention that the points must stay one on top of the other!
enter image source here
Starting from the last zero I get a #1# from the #7# (that becomes #6#) and I get #10-1=9#;
Next I get another #1# from the #4# (that becomes #3#) and I do #16-7=9#. The next will be the #3-0=3# and finally #8-5=3#.