Addition and Subtraction - Brandywine School District

The Brandywine School District presents

The Singapore Math Series Session 1I

Addition and 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 Addition 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

John read 50 pages altogether.

32 Part

? Whole

18 Part

Addition - Thousands 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