Get some addition practice while reading picture books together. There are a ton of great picture books that have overt and hidden addition facts and practice, but you can turn any book into a lesson in addition. If you read a page with a picture of a forest, you might say to your child, "I see three trees and four flowers. How many plants are there all together?" You can add characters, shapes, items, or anything in multiples.
Children may find the easiest way to work this out is by using the column method, where all the numbers are placed in a column, one on top of the other. It is vital that they remember that the decimal points of each number must line up. Once they’ve worked out using pencil and paper, let them check on a calculator as using decimals accurately on a calculator is an important real life skill too.