# Addition and Subtraction - Brandywine School District

```The Brandywine School District
presents
The Singapore Math Series
Session 1I
Subtraction
Created by Hester Sutton March 2011
A man sold 230 balloons at a carnival in
the morning. He sold another 86
balloons in the evening.
a) How many balloons did he sell in all?
b) How many more balloons did he sell in
the morning than in the evening?
A man sold 230 balloons at a carnival in
the morning. He sold another 86
balloons in the evening.
a) How many balloons did he sell in all?
Morning
Afternoon
230
86
?
A man sold 230 balloons at a carnival in the morning. He sold
another 86 balloons in the evening. How many did he sell in all?
Hundreds
Tens
Ones
3
1
6
Using Number Bonds
part + part = whole
230
316
whole
part
86
part
A man sold 230 balloons at a carnival in
the morning. He sold another 86
balloons in the evening.
a) How many balloons did he sell in all?
(230
230
300+16=316
+ 70)+16
86
(70+16)
316 balloons were sold in all.
A man sold 230 balloons at a carnival in
the morning. He sold another 86
balloons in the evening.
a) How many balloons did he sell in all?
b) How many more balloons did he sell in
the morning than in the evening?
A man sold 230 balloons at a carnival in
the morning. He sold another 86
balloons in the evening.
b) How many more balloons did he sell in
the morning than in the evening?
230
Morning
Evening
86
?
A man sold 230 balloons at a carnival in the morning. He sold
another 86 balloons in the evening. How many more balloons did he
sell in the morning than in the evening?
Hundreds
1
Tens
Ones
4
4
Using Number Bonds
Subtraction
whole - part = part
230
whole
86
part
144
part
Mary made 686 paper flowers. She sold some of them. If
298 were left over, how many flowers did she sell?
Using the Bar Model
Mary sold 384 flowers.
298
?
Mary’s
Paper
Flowers
686
686 - 298
686 – 300 + 2 = 386 + 2
= 388
Mary made 686 paper flowers. She sold some of them. If
298 were left over, how many flowers did she sell?
Using Number Bonds
?
Part
686
Whole
298
Part
686 - 298 = 388
hundreds
tens
ones
134 girls and 119 boys took part in an art competition. How
many more girls than boys were there?
Comparison bar model.
134
girls
boys
119
Using a mental math strategy:
134 - 119
134 – 120 + 1
14 + 1 = 15
There were 15 more girls than boys.
?
John read 32 pages in the morning. He read 14 fewer pages in the
afternoon.
a) How many pages did he read in the afternoon?
b) How many pages did he read altogether?
32
Morning
Afternoon
?
14
32 – 14 = 18
John read 18 pages in the afternoon.
14
Part
32
Whole
?
Part
John read 32 pages in the morning. He read 14 fewer pages in the
afternoon.
a) How many pages did he read in the afternoon?
b) How many pages did he read altogether?
32
Morning
?
Afternoon
18
32 + 18 = 50
32
Part
?
Whole
18
Part
A shop sold 957 beef burritos and 1238 chicken burritos. How
many burritos were sold altogether?
957
1238
?
957
Part
2195
Whole
1238
Part
957 +1238 = 2195
Thousands
Hundreds
Tens
Ones
The total weight of Peter, David, and Henry is 123 kg.
+ D +than
= 123
kgis 3 kg
Peter D+15
is 15 kg heavier
David.
David
D+3
lighter than Henry. Find Henry’s weight.
Peter
15kg
123 kg
David
Henry
3kg
D+15 + D + D+3 = 123 kg
D + D + D + 18 = 123 kg
D + D + D = 105 kg
D = 35 kg
H = (35 + 3)kg
H = 38 kg
Henry weighs 38 Kg
```