Start by explaining that tens always end in 0. Next explain that you can add by counting amounts. You first count how many you have, that is your first addend. Then you count how many are being added, that is your second addend. When you add them together, you get the total, or sum. Show this on the interactive whiteboard with the problems with dollars and cookies to discuss how to solve the problems. Check that students are able to add with the exercises with blocks and eggs. Ask students how they determined the total of the problem. Then practice with another kind of addition problem. Tell students that you can also count on to determine the total. Practice counting how many you have, and counting on with the second set of objects. Check that students understand counting on with a few exercises. Next discuss that you can solve addition problems in different ways. Say that you can use a number line, but you can also turn it into a subtraction problem. Say that you have to look closely at the problem to determine what the easiest way to solve it is. Ask students to solve a few problems and ask them how they calculated. Finally show them how to solve a story problem. Have them determine what kind of problem it is, which numbers are needed for the problem, to say or write the problem and then to solve for the answer.
Check that students can add to 100 making ten by asking the following questions:
- What do you look at when you want to solve a story problem?
- How do you calculate 23+7 and 48==70?