addition within 20
DESCRIPTION
TRANSCRIPT
• Building up number bonds• Use the addition symbol (+) to write
a mathematical sentence• Solving 1-step word problems involving addition
What will we learn today?
Whole Numbers
Addition Within 20
Number Bonds
whole
part
part
part + part = whole
We use this symbol to do addition.
2 and 3 make 5
2 + 3 = 5
There are 5 cars altogether.
5
2
3
Here’s an example.
10
?
?
To make 10, we can have a
few combination of
numbers.
1 and 9 make 10
2 and 8 make 10
3 and 7 make 10
4 and 6 make 10
5 and 5 make 10
Here’s another example.
8
?
6
whole = 81 part = 6
6 and 2 make 8.
Here’s another example.
By using the count-on method, you can easily add to find the answer.
+1+1+1
6 7 8
5 + 3 = 8
11
11 + 3 = 14
12
13
14
Here’s another example.
More than
4 more than 6 is __________.
4 + 6 = 10
5 more than 8 is __________.
5 + 8 = 13
Word Problem
Jane has 9 sweets. Her sister gives her 3 more sweets. How many sweets does Jane have now?
9 + 3 = 12
She has 12 sweets now.
Here’s another example.
Tommy bought 10 marbles. Ali bought 6 marbles. How many marbles did they have altogether?
10 + 6 = 16
They had 16 marbles altogether.
Are you ready to try out the questions?