When children initially learn addition, subtraction, multiplication, and division, they begin by performing operations on two numbers. But what happens when an expression requires multiple operations? Over time, mathematicians have developed a set of rules called the order of operations to determine which operation to do first.
Its realy easy put one number above the other put your decimales alined.add seros to the Numbers to have the same length. Then subtract is easy.
Ignore your decimal point, and then put your decimal at the same spot as the other one and then you divide as simple as it is.
In other words, just count up how many numbers are after the decimal point in both numbers you are multiplying, then the answer should have that many numbers after its decimal point.