Looking Back: Adding and Subtracting Within 20

Look for this idea outside of your lessons. These facts sit underneath every math class you will ever take. Strong here means steady later. This is worth learning because these facts are the ground floor of every math year ahead.

Watch for it today, and when you spot it, tell someone what you noticed and how you knew. Ask yourself where else the same idea might be hiding, then go and look.

Let us think about this slowly. Remember where you started. Now you add and subtract within twenty using several strategies: counting on, making ten, doubles and near doubles, counting up, and known facts.

You solve four kinds of story problems and find missing numbers in any position. Test yourself with 9 plus 6, 15 minus 8, and 7 plus blank equals 13, naming your strategy each time before you solve.

Try this honest check. Solve ten facts and mark the ones that took you longer than a few seconds. Those are the ones worth practicing this week. Everything else is already yours. Show your work to someone and explain it in your own words.