Representing Addition and Subtraction
Represent addition and subtraction using objects, drawings, and mental images
What a learner can do afterwards
- Use cubes or counters to model addition and subtraction within 10
- Draw and check a picture that shows a subtraction situation
- Use fingers to model a small addition or subtraction problem
1 · Read
You have joined groups and taken things away. Show each thing with one block, counter, finger, or mark. Addition joins groups. You can say 'plus'. Show both groups and count each thing once. You can also picture the groups in your mind.
To show subtraction, draw the starting group. Cross out one mark for each thing taken away. Count only the marks without crosses. Mia draws 6 apples and crosses out 1. She counts 5 apples left.
For 2 plus 1, raise 2 fingers on one hand and 1 on the other. Count all 3 raised fingers. For 5 take away 3, raise 5 fingers and fold 3 down. Count the 2 fingers still up.
Check both numbers in a model. For 7 take away 4, draw 7 dots and cross out 4. If only 1 has a cross, keep crossing dots and counting the crosses until you reach 4. With counters, move 4 away. Count only the counters that stayed.
Follow each change in order. For 1 block, 1 more, and 2 more, draw all three groups. Count 4 blocks. For 2 apples and 2 more, draw 4 apples. Then cross out 2 to show 2 taken away. Count the 2 apples left.
Show your addition and subtraction with objects, drawings, or fingers.
Lesson and practice text written for this dataset.
Readings and extra questions written for this dataset.
More to read
From blocks to marks
Set 1 block beside a group of 3 blocks. Touch each block once as you count. Your count ends at 4.
Make a mark on paper for each block. Draw 1 mark and then 3 more. There should be 4 marks, just as there are 4 blocks. Check that every block has one mark.
Two ways to show taking away
Put 7 counters on a mat. Slide 2 off the mat. Count the counters still on it: 1, 2, 3, 4, 5.
Try the same action on paper. Draw 7 circles and cross out 2. The circles without crosses stand for the counters still on the mat. Both models show 5 remaining.
Raised and folded fingers
Raise 3 fingers on one hand and 1 on the other. Count all the raised fingers. There are 4.
Keep those fingers raised, then fold 2 down. Look at the fingers still up. There are 2. Raising more fingers can show things joining. Folding fingers down can show things being taken away.
Check before counting
Draw a picture for 9 take away 3. First check that you drew 9 dots. Then check that exactly 3 dots have crosses.
If only 2 dots have crosses, put a cross on 1 more dot. Now the picture shows the requested action. Count the dots without crosses: 1, 2, 3, 4, 5, 6.
2 · Watch
به انگلیسیTake it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
17 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.