3
Zero and doubles
Joyful Mathematics: Chapter 5
GoalAdd zero to a number and add two equal groups.
New words
zero (0) · none at alldouble · two equal groups addedthe same · not changed
Explanation
When we add 0, nothing is added. 4 + 0 = 4. The number stays the same. Two equal groups make a double. 3 and 3 make 6. 4 and 4 make 8. Doubles are easy to remember.
Worked examples
5 + 0 = 5. There are 5 coconuts and an empty box. Nothing is added.
2 + 2 = 4. 2 shoes and 2 shoes make 4 shoes.
4 + 4 = 8. A cow has 4 legs. Two cows have 4 + 4 = 8 legs.
Class activity
Draw doubles. Fold a sheet of paper in half and open it. Draw 3 dots on the left half and 3 dots on the right half. Count all the dots: 3 + 3 = 6. Do the same with 1, 2, 4 and 5 dots on each side.
Practice
1
What is 7 + 0?
7.
2
How many cups altogether?
8.
3
How many dots in the two rows of the frame?
10.
4
Zoya has 0 sweets. Her mother gives her 3 sweets. How many sweets does Zoya have now?
3.
5
Which is a double: 3 + 3 or 3 + 4?
3 + 3.