2
Sums across and down
Joyful Mathematics: Chapter 5
GoalWrite an addition across and down, and find the same answer.
New words
across · from left to rightdown · from top to bottomsum · the answer when we add
Explanation
We can write a sum across. 2 + 3 = 5. We can also write it down. Write 2. Write 3 under it. Draw a line. The answer goes under the line. Across or down, the answer is the same. It is 5.
Worked examples
Across: 4 + 5 = 9. Down: 4 and 5 under it give 9 under the line.
Across: 1 + 7 = 8.
6 + 2 and 2 + 6 are written in different ways. Both sums are 8.
Class activity
Write it twice. The grown-up writes a sum across on a piece of paper, for example 3 + 4. The child writes the same sum down and finds the sum. Check with seven buttons. Try five different sums.
Practice
1
Add. What is the sum?
7.
2
Add. What is the sum?
8.
3
Write 2 + 6 down and add.
8.
4
Is 3 + 5 the same as 5 + 3?
Yes. Both are 8.
5
What is 4 + 4?
8.