The worksheet titled "Multi-Digit Addition up to Five Digits: Plus Addition and Subtraction Facts Practice" is full of multi-digit addition problems. Addends in each problem can have two, three, four, or five digits. Addends don't always have the same number of digits, either. For example, students add 1,245 + 3,345, but they might also add 1,799 + 484.

The right-hand column on the worksheet contains running addition and subtraction problems within 100. The answer can only be found after finding the solution to multiple addition and subtraction problems that utilize the answer as a number in the next problem. For example, students might start by adding 5 + 7. They fill "12" in the box, then add 8 to get the next answer, and so on, until they have added or subtracted over a dozen different numbers. Sometimes, students find the answer in the series, but sometimes, they must also find the addend or the number being subtracted instead.

Regular practice is important when students are learning to add. That's especially true when they're learning how to add large numbers with many digits. Giving them practice with different combinations of numbers and checking their answers frequently is a good way for teachers to gauge mastery.

It can also be helpful to give students unique ways to practice their addition skills. For example, you can give them a string of problems that all build on one another to find a final answer. For example, students might start by adding 6 + 8. They write the answer, then add 3, and so on until they get to the final answer of 40.