,

1. How many zeros

2. What will be the last digit of the product of
numbers 1 to 5
1 x 2 x 3 x 4 x 5 = 1 x 3 x 4 x 10
= 12 x 10
=120

3. How many zeros are there in
the product of first five
numbers?

4. Only one zero in the product

5. what about the product of numbers 1 to 10
= 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10
= 3 x 4 x 10 x 6 x 7 x 8 x 9 x 10
= 12 x 10 x 3024 x 10
= 36288 x 100
=3628800

6. How many zeros are there in
the product of first ten
numbers?

7. Two zeros in the product

8. How to multiply a number with 10,100,1000,....
Eg 5 x10 = 50
6 x 100 = 600
25 x 1000 = 25000
350 x 100 = 35000

9. When we multiply a number
with 10,100,1000,... just
multiply the numbers and put
the number of zeros to that
product

10. Rajeevan Master bought three packets of crayon,
each for 12 rupees, as prize for the quiz. After
the competition, two more children had to be given
prizes and so he bought two more packets. How much
did he spend in all?

11. First, he spent = 12 × 3 = 36 rupees
Then he spent = 12 × 2 = 24 rupees
So altogether he spent = 36 + 24 = 60 rupees

12. This can be done in a different way:
He bought 3 + 2 = 5 packets.
And the price of each packet is 12 rupees.
So he spent in all 12 × 5 = 60 rupees.
(3 + 2) × 12 = (3 × 12) + (2 × 12)