Unit 2

2.1 Definition of Addition

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Rule: Two numbers can be added in any order, the answer will always be the same.

The symbol of addition is (+).

6 + 4 = 10 ➔ 4 + 6 = 10 5 + 6 = 11 ➔ 6 + 5 = 11

Exercise 1

Add and check your answer.

3 + 8 = 11 8 + 3 = 11

9 + 4 = 13 4 + 9 = 13

5 + 7 = 12 7 + 5 = 12

2 + 9 = 11 9 + 2 = 11

8 + 2 = 10 2 + 8 = 10

9 + 9 = 18 9 + 9 = 18

Exercise 2

Write the missing number.

a 1 + 6 = 7

b 9 + 7 = 16

c 8 + 9 = 17

d 2 + 8 = 10

e 8 + 8 = 16

f 4 + 0 = 4

g 6 + 9 = 15

h 2 + 1 = 3

i 5 + 8 = 13

j 9 + 2 = 11

Unit 2

2.1 Addition Practice

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Exercise 3

Add.

a 12 + 15 = 27

b 26 + 20 = 46

c 34 + 12 = 46

d 34 + 14 = 48

e 13 + 26 = 39

f 22 + 23 = 45

Exercise 4

a Add 2 to each of the following numbers:

37 ➔ 39

476 ➔ 478

b Add 30 to each of the following numbers:

18 ➔ 48

888 ➔ 918

46 ➔ 76

840 ➔ 870

c Add 100 to each of the following numbers:

20 ➔ 120

850 ➔ 950

180 ➔ 280

238 ➔ 338

400 ➔ 500

333 ➔ 433

Unit 2

2.2 Adding without Regrouping

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Remember: Arranging the numbers vertically makes it easier to add.

① Add ones. ② Add tens. ③ Add hundreds. ④ Add thousands.

Exercise 1

Add:

a

8 2 3

+ 4 2

8 6 5

b

2 3 2

+3 4 2

5 7 4

c

2 1 3

+6 2 1

8 3 4

d

5 0

+2 0 5

2 5 5

e

5 2 3

+2 5 4

7 7 7

f

5 6 7

+4 2 1

9 8 8

Unit 2

2.2 Place Value Addition

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Exercise 2

What is the sum of each of the following?

a 342 + 123 = 465

b 344 + 234 = 578

c 421 + 124 = 545

d 325 + 523 = 848

e 723 + 232 = 955

f 123 + 243 = 366

Look at this example:

          Th  H  T  O

           2  5  1  0

          +   2  4  0

          -------------

           2  7  5  0

Exercise 3

Add:

a

Th H T O

4 5 7 6

+ 3 1 3

4 8 8 9

b

6 5 7 5

+ 4 2 1

6 9 9 6

c

6 8 2

+2 3 1 5

2 9 9 7

d

4 6 8

+5 4 3 0

5 8 9 8

e

2 2 5 1

+3 5 3 6

5 7 8 7

f

2 7 4 2

+3 2 3 3

5 9 7 5

Unit 2

2.3 Adding with Regrouping

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Concept: When there are more than 9 ones, regroup or trade 10 ones for 1 ten.

Write the numbers in the standard form:

3 tens and 13 ones = 43

4 tens and 4 ones = 44

4 tens and 16 ones = 56

5 tens and 7 ones = 57

Look at these examples:

            ①

             3 1 4

            +5 2 7

            -----

             8 4 1
          
            777 + 137:

            Add ones (7+7 = 14). Trade 10 ones for 1 ten. Add tens (1+7+3 = 11). Trade 10 tens for 1 hundred. Add hundreds (1+7+1 = 9). Result = 914.

Exercise 1

Add:

a

① ①

5 4 3

+ 5 6 7

1 1 1 0

b

① ①

3 4 5

+ 8 7 6

1 2 2 1

c

①

5 6 3

+ 4 6 4

1 0 2 7

d

①

4 3 4

+ 4 3 7

8 7 1

e

① ①

7 8 9

+ 6 9 7

1 4 8 6

f

①

4 5 6

+ 6 2 7

1 0 8 3

Unit 2

2.3 Regrouping 4-Digit Numbers

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Example: Add 7648 to 9875.

Exercise 2

Add.

a

Th H T O

6 4 5 6

+1 3 2 7

7 7 8 3

b

8 3 4 5

+1 3 5 6

9 7 0 1

c

8 4 5 6

+ 4 9 8 7

1 3 4 4 3

d

7 6 4 3

+ 4 2 7 9

1 1 9 2 2

e

6 7 5 6

+ 8 4 8 7

1 5 2 4 3

f

3 9 5 6

+4 5 4 3

8 4 9 9

Exercise 3

Copy and find.

a 7644 and 7856 ➔ 7644 + 7856 = 15,500

b 7856 and 8478 ➔ 7856 + 8478 = 16,334

Unit 2

2.4 Problem Solving

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Remember the 4 Steps:

1- Read. 2- Plan. 3- Solve. 4- Check.

Example 1: In a school, there are 64 boys and 39 girls. How many students are there in all?

Solution: Boys: 64 | Girls: 39 | Total: 64 + 39 = 103 students

Example 2: A man bought a car for $7,844 and furniture for $3,457. How much money did he spend altogether?

Solution: Car: $7,844 | Furniture: $3,457 | Total: $7,844 + $3,457 = $11,301

Exercise

Solve the following word problems.

1. A man traveled 136 km on the first day of his journey and 178 km on the second day. How many kilometres did he travel in two days?

Click for Solution: 136 + 178 = 314 km

Unit 2

2.4 Problem Solving (Continued)

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2. A shopkeeper has 349 apples in a basket and 547 apples in another basket. How many apples does he have in all?

Solution: 349 + 547 = 896 apples

3. Mr. Sami bought a chair for $150, and a table for $442. Find the total cost of the chair and the table.

Solution: $150 + $442 = $592

4. Two planes landed in the airport. If the first plane has 115 passengers and the other has 217 passengers, what is the total number of passengers in both planes?

Solution: 115 + 217 = 332 passengers

5. An orchard has 3456 mango trees and 7467 apple trees. How many trees are there in the orchard?

Solution: 3456 + 7467 = 10,923 trees