Multiplication by 1-digit number
Multiplying a 2-digit number by a 1-digit number
Multiplying a 2-digit number by a 1-digit number without carrying is straightforward because each product of the digits stays within single digits. Here’s how to do it:
Example: Multiply 23 by 3
1. Break Down the Number:
– The 2-digit number 23 can be split into 20 (tens place) and 3 (ones place).
2. **Multiply Each Part Separately:**
– Multiply the digit in the tens place by the 1-digit number:
20 times 3 = 60
– Multiply the digit in the ones place by the 1-digit number:
3 times 3 = 9
3. Add the Results:
– Add the two products together:
60 + 9 = 69
So, 23 times 3 = 69
Multiplying a 3-digit number by a 1-digit number
Multiplying a 3-digit number by a 1-digit number without carrying follows a similar process to the 2-digit case but with an extra step. You multiply each digit of the 3-digit number separately by the 1-digit number and then add the results.
Example: Multiply 231 by 2
1. Break Down the Number:
– The 3-digit number 231 can be split into 200 (hundreds place), 30 (tens place), and 1 (ones place).
2. Multiply Each Part Separately:
– Multiply the hundreds digit by the 1-digit number:
200 times 2 = 400
– Multiply the tens digit by the 1-digit number:
30 times 2 = 60
– Multiply the ones digit by the 1-digit number:
1 times 2 = 2
3. Add the Results:
– Add the three products together:
400 + 60 + 2 = 462
So, 231 times 2 = 462.
Multiplying a 2-digit number by a 1-digit number( with regrouping and carrying)
Explaining multiplication with regrouping and carrying in a simple, step-by-step way. Let’s break it down:
Example: Multiply 23 by 4
1. Set Up the Problem:
– Write the 2-digit number (23) on top.
– Write the 1-digit number (4) underneath, lining it up with the ones place of 23.
– Draw a line under the numbers where you’ll write the answer.
23
× 4
—–
2. Multiply the Ones Place:
– Start by multiplying the digit in the ones place of 23 (which is 3) by 4.
– 3 times 4 = 12
– Write the 2 from 12 under the ones column, and carry the 1 (the “ten”) over to the next column.
23
× 4
—–
2 (write the 2 here)
3. Multiply the Tens Place:
– Now, multiply the digit in the tens place of 23 (which is 2) by 4.
– 2 times 4 = 8
– Don’t forget to add the 1 you carried over: 8 + 1 = 9
– Write the 9 under the tens column.
23
× 4
—–
92
4. Final Answer:
– The numbers in the answer line (92) are the result of multiplying 23 by 4.
– So, 23 times 4 = 92.
Key Points :
– Carrying means moving the extra number from one column to the next.
– Regrouping happens when the product is 10 or more. You write down the ones digit and carry over the tens digit to the next column.
– Always start multiplying with the ones place, then move to the tens place.
Multiplying a 3-digit number by a 1-digit number( with regrouping and carrying)
Multiplying a 3-digit number by a 1-digit number with regrouping and carrying can be explained in simple steps. Here’s how you can do it:
Example: Multiply 243 by 5
1. Set Up the Problem:
– Write the 3-digit number (243) on top.
– Write the 1-digit number (5) underneath, lining it up with the ones place of 243.
– Draw a line under the numbers where you’ll write the answer.
243
× 5
—–
2. Multiply the Ones Place:
– Start by multiplying the digit in the ones place of 243 (which is 3) by 5.
– 3 times 5 = 15
– Write down the 5 under the ones column, and carry the 1 (the “ten”) over to the next column.
243
× 5
—–
5 (write the 5 here)
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3. Multiply the Tens Place:
– Now, multiply the digit in the tens place of 243 (which is 4) by 5.
– 4 times 5 = 20
– Don’t forget to add the 1 you carried over: 20 + 1 = 21
– Write the 1 under the tens column and carry the 2 (the “twenty”) over to the next column.
243
× 5
—–
15 (write the 1 and carry the 2)
4. Multiply the Hundreds Place:
– Now, multiply the digit in the hundreds place of 243 (which is 2) by 5.
– 2 times 5 = 10
– Add the 2 you carried over: 10 + 2 = 12
– Write the 12 in the hundreds and thousands place.
243
× 5
—–
1215
5. Final Answer:
– The numbers in the answer line (1215) are the result of multiplying 243 by 5.
– So, 243 times 5 = 1215.
Key Points :
– Carrying happens when the result of multiplying two digits is 10 or more. You write down the ones digit and carry over the tens digit to the next column.
– Regrouping is another word for carrying—moving the extra value to the next column.
– Always start multiplying from the right (ones place) and move to the left (tens, then hundreds).