5. multiplying 2 to 4 digit numbers by 1-to 2-digit

MULTIPLYING 2-TO 4 DIGIT NUMBERS BY

1-TO 2-DIGIT NUMBERS WITHOUT

REGROUPING

Basic multiplication facts

8x 1

3x 7

4x 0

9x 2

5x 6

10x 4

MESSAGE IN BOXESMULTIPLY. WRITE THE LETTER THAT

IS NEXT TO EACH ANSWER IN THE CORRECT BOX BELOW. READ THE SECRET MESSAGE. 9 4 3 9

5x 2 x 9 x 4 x 7 x 2 9 5 9

9 6x 8 x 9 x 9 x 3 x 9

A E H O R

WUTS Y

27

63

27

W O W

45

12

18

45

T H A T

72 81 10 36

S U R E

27 18 72

W A S

36 18 72 54

E A S Y

Andres Bonifacio Elementary School

received 12 boxes of toy from the governor of the province. Each box had 24 assorted toy. How many toys were there in all?

Understand the problem

• What is asked in the problem? Number of toys in all.

• What are given? 12 boxes of toys, 24 assorted toys

• What process will you use? Multiplication.

Plan

12 x 24 = N 24 = 20 + 4

x 12 = 10 + 2

CARRY OUT THE PLAN

Step 1:

20 + 4

x 10 + 2

40 + 8

2 x 4 = 8

2 x 20 = 40

Step 2:

20 + 4

x 10 + 2

200 + 40

10 x 4 = 40

10 x 20 = 200

Step 3:

24 = 20 + 4

x 12 = 10 + 2

40 + 8

+ 200 + 40

240 + 48 = 288 toy planes

ADD THE TWO PARTIAL PRODUCTS24

X 1248 PARTIAL PRODUCTS

+ 240 PRODUCT 288

Multiply by ones

24

x 12

48

240

Multiply tens

24 24

x 2 x1048

240

1) 22

x 11

3) 322

x 33

2) 322

x 3

4)1 243

x 12

GROUP ACTIVITY ( 4 GROUPS )Group I

=

Group II =

Group III =

Group IV

=

124

x 2

221

x 4

213

x 13

212

x 3

6321

x 12

32 412

x 12

4 213

x 12

2 134

x 12

21

x 21

13

x 12

14

x 2

23

x 13

Remember:

In multiplying 2- to 4- digit numbers by 1- to 2- digit numbers without regrouping, start with the

one, then the tens, then the hundreds, and lastly the

thousands.

Pick a number from box X. Multiply it by a number from box Y. Write the numbers for X and Y that are equivalent to the given answers below.

42 22 123

23 31 431

21 12 32

24 33 20

Box X

Box Y

1)483X= Y=

4)504X=Y=

2) 8620 X= Y=

5) 528 X= Y=

3) 3936 X= Y=

6) 1023 X= Y=

EXERCISE:Find the missing digits

1) 2 3 4 2 2 + 4 8 68 5 4 8

4) 3 2 x 1 2

2 3 8 4

5) 1 2 3 x 1 3 6 9

12 1 9 9

2) 4 3 2 1 x 2 3 1 2 9 8 42 9 9 8 3

3) 2 4 x 1 1

2

6 4

ASSIGNMENT:Solve the following problems:

1. Ellen has 23 pages of stamps. Each page has 112 pieces. How many stamps does she has in all?

2. Mang Mario needs 4 poles for his vegetable garden. Each pole should be 122 centimeters long. What will be the total length of 4 poles.

3. The bookstore received a shipment of 13 boxes of books. Each box contained 112 books. How many books were in the shipment?

4) Puring and Linda are going home after visiting their grandmother. The trip takes 3 hour. If the bus travels 122 kilometers an hour, how far away is their house?

5) Edith bought 231 pieces of linen paper at P3 each. How much did she spend for the linen paper?