Lesson ⁦3-4⁩: Multiply by a One-Digit Number

Math · Fifth Grade, Primary · Unit 3: Multiplication · First Semester

A 10-question quiz; after every question you'll see the right answer with an explanation.
Earn 5 points for every new star.

Log in and start 🚀

No account? Create one for free

What will you learn in this lesson?

Students multiply numbers with two or more digits by a 1-digit number using the vertical method with regrouping, a basic skill in everyday calculation.

  • Multiplies whole numbers by a 1-digit number with regrouping
  • Multiplies numbers containing zeros by a 1-digit number
  • Estimates the product to check whether the answer is reasonable

💡 Tip: Start with the ones and write the carried digit above the next place, and add it after multiplying, not before.

🤖 Ask Ghada about the lesson

Ghada explains the lesson and answers your questions about it. Log in to get started.

Worked examples from the Multiply by a One-Digit Number lesson questions

Find 34 × 6
  • 204
  • 184
  • 214
  • 194
✓ 204
4 × 6 = 24, write 4 and carry 2, then 3 × 6 = 18, and 18 + 2 = 20, so the answer is 204.
Find 128 × 4
  • 512
  • 482
  • 412
  • 522
✓ 512
8 × 4 = 32 (write 2, carry 3), 2 × 4 + 3 = 11 (write 1, carry 1), 1 × 4 + 1 = 5, so the answer is 512.
Show more examples (3)
Find 2,305 × 3
  • 6,915
  • 6,905
  • 6,015
  • 6,951
✓ 6,915
5 × 3 = 15, 0 × 3 + 1 = 1, 3 × 3 = 9, 2 × 3 = 6, so the answer is 6,915.
Find 459 × 7
  • 3,213
  • 2,853
  • 3,153
  • 3,203
✓ 3,213
9 × 7 = 63 (write 3, carry 6), 5 × 7 + 6 = 41 (write 1, carry 4), 4 × 7 + 4 = 32, so the answer is 3,213.
A bicycle costs 685 riyals. How much do 5 bicycles cost?
  • 3,425 riyals
  • 3,025 riyals
  • 3,405 riyals
  • 3,325 riyals
✓ 3,425 riyals
685 × 5: 5 × 5 = 25, 8 × 5 + 2 = 42, 6 × 5 + 4 = 34, so the answer is 3,425 riyals.

FAQ about the Multiply by a One-Digit Number lesson

How do I calculate 459 × 7?

7 × 9 = 63: write 3 and carry 6. Then 7 × 5 = 35 + 6 = 41: write 1 and carry 4. Then 7 × 4 = 28 + 4 = 32, so the product is 3,213.

What do I do when there is a zero in the number, such as 2,305 × 3?

Multiplying by zero gives zero, but we add the carried digit if there is one. 3 × 5 = 15: write 5 and carry 1; 3 × 0 = 0 + 1 = 1. The product is 6,915.

How do I study the lesson Multiply by a One-Digit Number and test myself on it?

Start the lesson quiz on Study with Ghada: 10 questions from the Math Fifth Grade, Primary question bank. After each answer you'll see the right answer with an explanation, and any questions you miss move to “Review my mistakes” until you master them.

Are Study with Ghada quizzes free and aligned with the curriculum?

Yes, completely free. They're built on the Math - Grade 5 - Semester 1 lessons in the same order as the book, and every question is reviewed and approved by a teacher before students see it.