Question 1

We need to calculate a product and then read the number in two systems.

Step 1 — Calculate the product

Let us find the value of the given multiplication. We will multiply 6400 by 62,500.

$6400 \times 62,500$

We can rewrite the numbers to make multiplication easier. $= (64 \times 100) \times (625 \times 100)$

Let us multiply 64 by 625 first. $= 40,000 \times (100 \times 100)$

Now, we multiply by the powers of 10. $= 40,000 \times 10,000$

We can count the total number of zeros. $= 400,000,000$

$\boxed{400,000,000 \text{ litres}}$

Step 2 — Read the number in Indian system

We will write the number 400,000,000 using the Indian numbering system. In this system, we group digits as 3, 2, 2, and so on from the right. The number is 40,00,00,000. This is read as forty crore.

$\boxed{\text{Forty Crore}}$

Step 3 — Read the number in American system

We will write the number 400,000,000 using the American numbering system. In this system, we group digits as 3, 3, 3, and so on from the right. The number is 400,000,000. This is read as four hundred million.

$\boxed{\text{Four Hundred Million}}$

Step 4 — Thoughts and questions about the fact

The Amazon river discharges 400,000,000 litres of water every second. This is an incredibly large amount of water. It shows how powerful and vast the Amazon river is. It is amazing that freshwater can be found so far into the ocean. This means the river's outflow is very strong. A question could be: How many Olympic swimming pools would this fill every second? Another question could be: How does this amount compare to the total water used by a large city in a day?

Answer

(i) The product is 400,000,000. (ii) In the Indian naming system, the number is Forty Crore. (iii) In the American naming system, the number is Four Hundred Million.