When we want to add or subtract decimals, we follow exactly the same procedure as adding and subtracting integers. The important thing is to write the numbers so that the corresponding digits are lined up in columns.
This video demonstrates the process for addition:
And this video demonstrates the process for subtraction:
We can practice these with our teacher:
Now let’s try the following exercise (without using our calculators, other than to check answers afterwards) from exercise 10B in our textbooks:
Here are the answers: