Using the images on the interactive whiteboard, explain to students how to add using the flags. You count the total number of flags, drag one more to the row, and then count the total again. Explain to students that since you are adding one more, you count one more. Repeat this with demonstrating adding with the apples. Tell students that you do the same when adding two to a number. Then explain to students that you can also take 1 and 2 away. Show the fish in the pond. Count the fish, and then drag one fish into the bucket and then count the fish again. Repeat this explanation with the bottles. Tell students that you do the same when subtracting two from a number. To check that students are able to add and subtract one or two to a given number with visual support, ask them to solve the problems on the interactive whiteboard individually or in pairs. Finally show students that they can also solve these problems when just numbers are shown. Emphasize to students that you are adding by counting one or two forward, and subtracting by counting one or two backward.
To check that students understand how to add or subtract numbers to 10 with one or two, you can ask the following questions:
- What does + mean?
- What does - mean?
- What do you do if you want to know how much 5 + 1 is?
- What do you do if you want to know how much 8 - 2 is?