1. Multiplying 2-to
4-Digit Numbers
by Multiplies of
10

2. Find the product.
a)21 b) 122 c) 3 012
x 5 x 6 x 4
d) 4 024 e) 313
x 2 x 3

3. In a toy factory, a group of
workers filled the 21
boxes with 50 toy cars
each. How many toy cars
were filled in the boxes?

4. What is asked? ( the total number of
toy cars that were filled in all the
boxes)
What are the given facts? ( 21 boxes
and 50 toy cars )
What shall we do find the answer? (
multiply )
What is the number sentence for the
problem? (21 x 50 = N)

5. Step 1
21
x 50
00
Step 2
21
x 50
00
105
Step 3
21
x 50
00
105
1050
( 1 050 toy cars were filled in all
boxes )

6. 0
10 20 30 40 50 60 70 80 90 100 110 120 130
How many zeros are there in 12 tens?
How many zeros are there in 10?
What did you do with zero?
12
x 10 or 12 x 10 = 120
120

7. a. To multiply by a multiple of 10,
multiply the non-zero digits first,
and then annex zeros in the
product.
b. The number of zero in the factors
is equal to the number of zeros in
the product.

8. Solve the following problems:
1. There are 165 trays of oranges. Each
tray has 20 oranges. How many are
there in all?
2. Grade 3 SPED A class has 43 pupil.
Each pupil has 10 books each. How
many books did they have altogether?
3. If there are 24 bottles in a case, how
many bottles will there be in 30
cases?

9. Exercise:
1) 36
x 10
2) 25
x 20
3) 45
x 30
4) 232
x 20
5) 9 201
x 30
a. 36
a. 2 520
a. 1 350
a. 2 320
a. 276 030
b. 360
b. 2 500
b. 1 530
b. 6 420
b. 270 603
c. 3 610
c. 500
c. 1 340
c. 4 640
c. 273 060

10. Assignment:
A.Answer the following:
1) 73 x 10 =
2) 25 x 30 =
3) 15 x 10 =
4) 62 x 10 ( <,>,= ) 60 x 10
5) 43 x 20 ( <,>,= ) 53 x 10

11. B. Find the product:
1)77 x 10 =
2)250 x 20 =
3)2 248 x 20 =
4)1 623 x 30 =
5)4 132 x 40 =