PRIMARY 1
Rev Up! Math
Name
Tutor
Topic Addition and Subtraction Within 20 (Lesson 11)
Addition and Subtraction Within 20 (Lesson 11)
Primary 1: Rev Up! Math
Add by counting on
10 11 12 13 14 15 16 17 18 19 20
Add by making 10 first Ring a set
of 10 first,
8 + 9 = 10 + then add.
=
We can also
use number
bonds to make
10 first.
8+9=
Add by counting back
9 10 11 12 13 14 15 16 17 18 19 20
Subtract from 10 first 1
14 - 9 =
4 10 10 – 9 =
+4 = 5
So, 14 – 9 =
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Primary 1: Rev Up! Math
Exercise 1: Add or subtract using the counting on or counting back
method.
Hello children! Please help us
count the number of food items
we have collected each day for
this week. Youcan use the
number line below to help you!
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
a) 8 + 7 = b) 9 + 9 =
c) 20 - 6 = d) 17 - 9 =
e) 5 more than what we
have collected on Thursday.
Answer:
f) 7 less than what we have Sunday is our rest and play
collected on Tuesday. day! We work hard and play
Answer: hard too.
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Exercise 2: Add by making 10 first. Primary 1: Rev Up! Math
1) Ring a set of 10, then add.
Children, I have
(a) learnt my lesson
8 + 7 = 10 + and am now
= collecting food items
(b) to prepare for
winter. But I can’t
add properly.
Please help me.
6+9= +
=
2) 5 + 7 =
3) Add 7 to 9. The answer is
4) Add 8 and 6. The answer is .
.
5) Add 6 and 7. The answer is
6) 8 + 9 = 3
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Exercise 3: Subtract from 10 first. Primary 1: Rev Up! Math
1) 15 – 6 =
Do not put off what you can
do today till tomorrow.
2) Subtract 8 from 17. The answer is .
3) 17 - 9 =
4) Subtract 8 from 16. The answer is .
5) 13 - 5 =
6) 14 - =8
7) 18 - 9 =
8) 17 - =9 4
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Primary 1: Rev Up! Math
Exercise 4:
1. Fill in the missing numbers in shapes with an ant in the puzzle below.
7+ = 16
+ _ =+
_=
= += = =
17 + 3 = 20
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Primary 1: Rev Up! Math
2. Arrange the answers below from the smallest to the greatest.
8+5= 15 – 7 = 13 + 7 = 20 – 5 =
,,,
smallest
3 Fill in the boxes with 14, 13, 7 or 5. You may use the numbers more
than once.
+ = 20
- =6
4. + = 17 Value:
If = 9, Hard work pays off!
=
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Primary 1: Rev Up! Math
*Exercise 5: Fill in the blanks with numbers 1 to 9 so that the
numbers will add up to 15 diagonally, horizontally and
vertically. Use each number only once.
1. 1 ( ) 6 + 1 + ? = 15
6
() () 3 ? + ? + 3 = 15
2 () ( ) 2 + ? + ? = 15
6 + ? + 2 = 15 1 + ? + ? = 15 ? + 3 + ? = 15 Hints
2. 3 ()
4
( )( ) 1
2 ( )( )
Value:
Doing it right!
There is a right time for work
and a right time for play.
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