1
Taking some away
Joyful Mathematics: Chapter 5
GoalTake some things away and say how many are left.
New words
take away · make a group smallerleft · what stays after we take some awayminus (−) · the sign for take away
Explanation
On Diwali night there are 8 oil lamps. The wind blows out 3 lamps. Cross them out. Count the lamps that are still lit: 5. 8 take away 3 leaves 5. We write 8 − 3 = 5. The sign − says minus.
Worked examples
9 mangoes are in a basket. 5 are sold. 4 are left. 9 − 5 = 4.
7 birds sit on a wire. 5 fly away. 2 are left. 7 − 5 = 2.
6 − 0 = 6. If we take away none, all of them are left.
Class activity
Story with buttons. Put 7 buttons on a cloth. Tell a story: 7 sheep are in a field and the shepherd takes 3 sheep into the barn. Slide 3 buttons away. Count how many are left. Say: "7 minus 3 equals 4." Make up two more stories.
Practice
1
7 fish are in the pond. Some are crossed out. How many fish are left?
5.
2
What is 7 − 4?
3.
3
9 pears. The crossed ones have been eaten. How many pears are left?
3.
4
Ananya has 5 sweets. She gives 1 to her friend. How many sweets are left?
4.
5
What is 4 − 4?
0.