Lesson 9
Focus on Problem Sums (1)
Concept: Part-Whole
Name : _____________________Teacher: ____________
Date : __________Day: ___________ Time: ___________
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Activity 1: Identifying parts and whole in story sums
5 ducks are swimming in the lake.
3 ducks are on land.
How many ducks are there in all?
Ans :
There are 14 eggs.
Mother uses 9 eggs to bake a cake.
How many eggs are left?
Ans :
Father used 3 stamps
and had 5 stamps left.
How many stamps did he have
at first?
Ans :
Jon sat for a Mathematics test.
The total mark for the test was 10.
He made 3 mistakes and lost
3 marks. What was Jon’s mark?
Ans :
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Lesson 9 Page 1
Mother has 10 cups.
2 of them are red and the rest are
blue?
How many cups are blue?
Ans :
Peter bought 15 sweets. He gave
9 sweets to his friend and ate the rest.
How many sweets did he eat?
Ans :
Amy has 11 seashells.
Her sister gives her 4 seashells.
How many seashells does Amy
have now?
Ans :
Dan made some paper airplanes.
He lost 2 airplanes. He has 5 paper
airplanes left.
How many paper airplanes
did Dan make at first? Ans :
Mary borrows 7 books from the
Library. Lisa borrows 2 books and
Tim borrows 3 books. How many
Problem Sums - Guided Examples
books do they borrow altogether?
Ans :
1.
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Lesson 9 Page 2
Problem Sums - Guided Examples
1. Peter has 4 balloons. Jane has 3 balloons.
How many balloons do they have altogether?
Pictorial
Number Bonds
Model
Equation
Word sentence
They have_______ balloons altogether.
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Lesson 9 Page 3
2. Mrs Lim bakes 10 cupcakes.
She gives 3 cupcakes to her friend.
How many cupcakes does Mrs Lim have left?
Pictorial
Number Bonds
Model
Equation
Word sentence
She has _______cupcakes left.
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Lesson 9 Page 4
3. Linda bought 3 candies from a sweet shop.
Jenny bought 5 candies and Ron bought 2 candies.
How many candies did they buy in all?
Pictorial
Number Bonds
Model
Equation
Word sentence
They bought _______ candies in all.
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Lesson 9 Page 5
4. Ron bought 12 buns.
He gave 3 buns to his brother and 4 buns to his sister.
How many buns were there left?
Pictorial
Number Bonds
Model
Equation
Word sentence
There were _______ buns left.
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Lesson 9 Page 6
5. Mother buys 11 eggs
She uses some eggs to make omelets and 3 eggs are left.
How many eggs does Mother use?
Pictorial
Number Bonds
Model
Equation
Word sentence
Mother uses _______ eggs.
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Lesson 9 Page 7
6. Jane has some ribbons.
She gives 3 to her sister and has 6 left.
How many ribbons does she have at first?
Pictorial
Number Bonds
Model
Equation
Word sentence
She has _______ ribbons at first.
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Lesson 9 Page 8
On Your Own (Homework)
Identifying parts and whole in story sums.
Ken has 2 blue pens and
3 red pens.
How many pens does Ken have
In all?
Ans :
6 passengers came out of the bus.
5 passengers were left in the bus.
How many passengers were
there in the bus at first?
Ans :
There were 8 slices of cakes.
Sam and his sister ate 3 slices
altogether. How many slices of
cakes were left?
Ans :
Mother buys 12 eggs. She uses 2 eggs
to bake cookies and 4 eggs to bake
muffins. How many eggs has she
left?
Ans :
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Lesson 9 Page 9
Problem Sums – On Your Own
1. Ben has 7 pencils.
His mother gives him 5 pencils.
How many pencils does Ben have now?
Pictorial
Number Bonds
Model
Equation
Word sentence
Ben has _______ pencils now.
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Lesson 9 Page 10
2. There are 10 fish in the tank.
Mrs Tan takes 3 fish out from the tank.
How many fish are there in the tank now?
Pictorial
Number Bonds
Model
Equation
Word sentence
There are _______ fish now.
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Lesson 9 Page 11
3. A clown gives 4 balloons to Annie, 2 balloons to Ben and 3
balloons to Ryan.
How many balloons do the children have in all?
Pictorial
Number Bonds
Model
Equation
Word sentence
They have _______ balloons in all.
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Lesson 9 Page 12
4. There are 9 flowers in a vase.
3 of them are blue and 2 of them are red.
The rest of the flowers are yellow.
How many yellow flowers are there?
Pictorial
Number Bonds
Model
Equation
Word sentence
There are _______ yellow flowers.
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Lesson 9 Page 13
5. Jen bought 12 strawberries. She used some to decorate a
cake. She had 7 strawberries left.
How many strawberries did she use to decorate the cake?
Pictorial
Number Bonds
Model
Equation
Word sentence
She used _______ strawberries to decorate the cake.
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Lesson 9 Page 14
6. Nan lost 5 erasers.
He had 2 erasers left.
How many erasers did he have at first?
Pictorial
Number Bonds
Model
Equation
Word sentence
Nad had _______ erasers at first.
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Lesson 9 Page 15
Note to Parents:
This week we focus on Problem Sums: Part Whole concept
We are moving away from concrete materials.
Lesson 9:
part + part = whole
whole – part = part
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Lesson 9 Page 16