Pengi Editor's Note: This article was originally published by Think Academy. We're sharing it here for educational value. Think Academy is a leading K-12 math education provider.
How to Multiply 2-Digit by 1-Digit Numbers in 3 Simple Steps
Multiplying a 2-digit number by a 1-digit number is a key math milestone introduced in Grades 2 and 3. Common challenges include forgetting to carry over, confusing place value, and skipping steps. This guide breaks the process into clear, simple steps.
3 Simple Steps to Multiply a 2-Digit Number by a 1-Digit Number
Let's walk through an example: 27 × 5
Step 1: Break the 2-Digit Number into Tens and Ones
Split 27 into two parts:
- 20 (Tens)
- 7 (Ones)
So: 27 = 20 + 7
Step 2: Multiply the Ones Place
7 × 5 = 35
Write down the 5 in the Ones place and carry over the 3 to the Tens place.
Step 3: Multiply the Tens Place and Add the Carry-Over
2 × 5 = 10
Then add the 3 carried over: 10 + 3 = 13
Final Answer: 27 × 5 = 135
Practice Examples
Example 1: No Regrouping
21 × 3 = ?
- 1 × 3 = 3
- 2 × 3 = 6 → becomes 60
Final Answer: 63
Example 2: With Regrouping
68 × 7
- 8 × 7 = 56 → write down 6, carry over 5
- 6 × 7 = 42, plus 5 = 47
Final Answer: 476
Summary: Key Steps to Master 2-Digit by 1-Digit Multiplication
- Break the 2-digit number into Ones and Tens
- Multiply the Ones place first and carry over if needed
- Multiply the Tens place, then add the carry-over
- Double-check your final answer
With consistent practice, students gain confidence in both mental math and long multiplication — a skill that benefits them throughout elementary school and beyond.
Try Pengi AI — Smarter Math Practice for Students
Pengi AI supports K–12 learners with personalized math practice, guided explanations, and feedback designed to help them build confidence and improve steadily.
