🎓 Mini-Lesson: How to Do Long Multiplication
What is Long Multiplication?
Long multiplication is a method we use to multiply larger numbers. It breaks the multiplication into smaller, easier steps!
📝 Steps for Long Multiplication:
- Write the numbers one under the other, with the bigger number on top
- Multiply the top number by the ones digit of the bottom number
- Multiply the top number by the tens digit of the bottom number (add a 0 first!)
- Add the two results together to get your final answer
Example 1: 234 × 12
Step 1: Write the numbers
234
× 12
-----
Step 2: Multiply by 2 (the ones digit)
234
× 12
-----
468 ← (234 × 2)
Step 3: Multiply by 1 (the tens digit), add a 0
234
× 12
-----
468
2340 ← (234 × 10)
-----
Step 4: Add them together
234
× 12
-----
468
2340
-----
2808 ← Final Answer!
234
× 12
-----
Step 2: Multiply by 2 (the ones digit)
234
× 12
-----
468 ← (234 × 2)
Step 3: Multiply by 1 (the tens digit), add a 0
234
× 12
-----
468
2340 ← (234 × 10)
-----
Step 4: Add them together
234
× 12
-----
468
2340
-----
2808 ← Final Answer!
Example 2: 45 × 23
45 × 3 = 135 (multiply by ones digit)
45 × 20 = 900 (multiply by tens digit)
135 + 900 = 1,035 (add them together)
45 × 20 = 900 (multiply by tens digit)
135 + 900 = 1,035 (add them together)
💡 Top Tips:
- Always line up your numbers carefully
- Don't forget to add the zero when multiplying by the tens digit!
- Check your work by estimating first
- Take your time and work through each step carefully
✏️ Practice Questions
Calculate each multiplication. Show your working if it helps!