Find area of shape . Show explanation please

The simplest area calculations are for rectangles. To find the area of a rectangle is Height by Width (HW). For a square its side by side

*add*

first lets take and example using 0.1 and 0.2

0.1

+0.2

=0.3

p/s : make sure the decimal points are alligned

*subtract*

we use the same rule as the above make sure the decimal point are alligned

0.2

-0.1

=0.1

*mutiply*

first vanish the decimal points

example 0.2 becomes 2.

if 0.9 becomes nine

then after you mutiply it, put the decimal point back where it should be

hope this helps! have a good day :)