Multiply numbers ending in zeroes: word problems

Key notes:

✨ Key Points

Numbers ending in zeroes can be written as a number × 10, 100, 1000, etc.

  • Example: 300 = 3 × 100
  • Example: 5,000 = 5 × 1,000

Steps to multiply numbers ending in zeroes:

  • Step 1: Ignore the zeroes and multiply the main digits.
  • Step 2: Count the total number of zeroes in both numbers.
  • Step 3: Add those zeroes back to the product.

Word problems often involve quantities, money, distance, or objects.

📝 Solved Examples

Example 1:
A school bought 200 chairs. Each chair costs 400 rupees. What is the total cost?

👉 Solution:

  • Multiply the main digits: 2 × 4 = 8
  • Count zeroes: 200 has 2 zeroes, 400 has 2 zeroes → total = 4 zeroes
  • Add them: 8 + 0000 = 80,000

✅ Total cost = ₹80,000

Example 2:
A farmer has 300 bags of wheat. Each bag contains 500 kg. How much wheat in total?

👉 Solution:

  • Multiply main digits: 3 × 5 = 15
  • Zeroes: 300 (2 zeroes) + 500 (2 zeroes) = 4 zeroes
  • Add them: 15 + 0000 = 150,000

✅ Total wheat = 1,50,000 kg

Example 3:
A bus travels 250 km every day. How many kilometers will it travel in 30 days?

👉 Solution:

  • Multiply main digits: 25 × 3 = 75
  • Zeroes: 250 (1 zero) + 30 (1 zero) = 2 zeroes
  • Add them: 75 + 00 = 7,500

✅ Total distance = 7,500 km

✨ Key Points
  1. A factory produces 600 toys every day. How many toys in 400 days?
  2. A pen costs 120 rupees. What is the cost of 200 pens?
  3. A train is 500 meters long. What is the total length of 300 such trains?
  4. A box contains 2,000 apples. How many apples in 400 boxes?
  5. A rope is 150 meters long. Find the length of 20 such ropes.

Learn with an example

🎇 Tristan filled 50 plates with biscuits. He put 30 biscuits on each plate. How many biscuits did Tristan use?

______ biscuits

There were 50 plates, each of which had 30 biscuits. Multiply 50 by 30.

First, multiply 5 and 3.

5 × 3 = 15

Now count the zeros in both numbers.

50 × 30 = ?

There are 2 zeros in all. Write 2 zeros after 15.

50 × 30 = 1,500

Tristan used 1,500 biscuits.

✨ A school ordered 10 boxes of paper. There were 60 sheets of paper in each box. How many sheets of paper did the school order in all?

_______ sheets of paper

The school ordered 10 boxes, each of which had 60 sheets of paper. Multiply 10 by 60.

First, multiply 1 and 6.

1 × 6 = 6

Now count the zeros in both numbers.

10 × 60 = ?

There are 2 zeros in all. Write 2 zeros after 6.

10 × 60 = 600

The school ordered 600 sheets of paper in all.

🎁 A seed company filled 80 bags with seed. They put 80 grams of seed in each bag. How many grams of seed are there in all the bags combined?

 ________ grams of seed

There are 80 bags with 80 grams of seed in each. Multiply 80 by 80.

First, multiply 8 and 8.

8 × 8 = 64

Now count the zeros in both numbers.

80 × 80 = ?

There are 2 zeros in all. Write 2 zeros after 64.

80 × 80 = 6,400

There are 6,400 grams of seed in all.

Let’s practice!