When you have equal groups and want to find the total, you can use repeated addition or multiplication.
Imagine you are buying bananas. The bananas come in bunches of 3. You buy 5 bunches:
To find the total number of bananas, you could add five 3s using repeated addition.
Or, you could show this same problem using multiplication!
3 times 5 means the same thing as adding 3 five times.
You can solve any multiplication problem using repeated addition. Just rewrite the problem and add.