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Lesson ⁦5-8⁩: Multiply a Three-Digit Number by a One-Digit Number

Math · Fourth Grade, Primary · Unit 5: Multiplying by a One-Digit Number · First Semester

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What will you learn in this lesson?

In this lesson we multiply a three-digit number by a one-digit number, regrouping when needed, such as 4 × 235. We multiply the ones, then the tens, then the hundreds, in order.

  • Multiplies a three-digit number by a one-digit number
  • Regroups in more than one place
  • Estimates the product to check that it is reasonable
  • Solves real-life problems involving prices and distances

💡 Tip: If the number has a zero, as in 3 × 405, multiply the zero and then add the carried digit: 3 × 0 + 1 = 1, and the product is 1,215.

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

What is 213 × 3?
  • 639
  • 216
  • 636
  • 539
✓ 639
3 × 3 = 9 ones, 1 × 3 = 3 tens, and 2 × 3 = 6 hundreds, so the answer is 639.
What is 120 × 4?
  • 480
  • 124
  • 840
  • 408
✓ 480
0 × 4 = 0 ones, 2 × 4 = 8 tens, and 1 × 4 = 4 hundreds, so the answer is 480.
Show more examples (3)
What is 302 × 2?
  • 604
  • 304
  • 640
  • 600
✓ 604
2 × 2 = 4 ones, 0 × 2 = 0 tens, and 3 × 2 = 6 hundreds, so the answer is 604.
What is 145 × 3?
  • 435
  • 325
  • 415
  • 148
✓ 435
5 × 3 = 15: we write 5 and regroup 1. 4 × 3 = 12 + 1 = 13: we write 3 and regroup 1. 1 × 3 = 3 + 1 = 4, so the answer is 435.
What is 256 × 4?
  • 1,024
  • 824
  • 1,004
  • 924
✓ 1,024
6 × 4 = 24: we write 4 and regroup 2. 5 × 4 = 20 + 2 = 22: we write 2 and regroup 2. 2 × 4 = 8 + 2 = 10, so the answer is 1,024.

FAQ about the Multiply a Three-Digit Number by a One-Digit Number lesson

How do I multiply 4 × 235?

4 × 5 = 20: write 0 and carry 2. Then 4 × 3 = 12 + 2 = 14: write 4 and carry 1. Then 4 × 2 = 8 + 1 = 9, so the product is 940.

How many digits are in the product of a three-digit number and a one-digit number?

Three or four digits. Example: 2 × 312 = 624 has three digits, and 5 × 312 = 1,560 has four digits.

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

Start the lesson quiz on Study with Ghada: 10 questions from the Math Fourth 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 4 - Semester 1 lessons in the same order as the book, and every question is reviewed and approved by a teacher before students see it.

Unit 5 lessons: Multiplying by a One-Digit Number

⁦5-1⁩ Factors and Multiples ⁦5-2⁩ Multiply by Multiples of 10, 100, and 1,000 ⁦5-3⁩ Problem-Solving Skill: Estimate Whether an Answer Is Reasonable ⁦5-4⁩ Estimate Products ⁦5-5⁩ Multiply a Two-Digit Number by a One-Digit Number Without Regrouping ⁦5-6⁩ Multiply a Two-Digit Number by a One-Digit Number with Regrouping ⁦5-7⁩ Problem-Solving Investigation: Choose the Best Strategy All Math Fourth Grade, Primary lessons →
← ⁦5-7⁩ Problem-Solving Investigation: Choose the Best Strategy ⁦6-1⁩ Multiply by Multiples of Ten →