Multiplication
In this article, the lesson objectives are:
- Multiplication of \(4-\)digit numbers by \(1-\)digit numbers
- Multiplication by \(10\) and its multiples
- Multiplication of \(2-\)digit numbers by \(2-\)digit numbers
- Multiplication of \(3-\)digit numbers by \(2-\)digit numbers
In Primary \(2\) and \(3\), we have learnt the multiplication tables of \(1\) to \(10\).
Question 1:
Solve the following multiplication.
\(8 × 9 =\) __________
- \(54\)
- \(56\)
- \(64\)
- \(72\)
Solution:
\(8 \times 9 = 72\)
Answer:
\((4) \;72\)
Question 2:
Solve the following multiplication.
\(18 \times 7 =\) __________
- \(124\)
- \(126\)
- \(134\)
- \(136\)
Solution:
Answer:
\((2) \;126\)
1. Multiplication Of 4-Digit Numbers By 1-Digit Numbers
The multiplication of \(4-\)digit numbers by \(1-\)digit numbers is similar to the multiplication of \(3-\)digit numbers by \(1-\)digit numbers.
Example:
\(1936 × 7 =\) __________
Solution:
Step 1:
Step 2:
Step 3:
Step 4:
Answer:
\(13 \,552\)
Question 1:
Solve the following multiplication.
\(3918 \times 5 =\) __________
Solution:
Answer:
\(19 \,590\)
2. Multiplication By 10 And Its Multiples
When we multiply a whole number by \(10\), we add one ‘\(0\)’ after the number.
For instance,
\(\begin{align*} 5 \times 10 &= 50 \\ 15 \times 10 &= 150 \\ 215 \times 10 &= 2150 \end{align*}\)
What do you think happens when we multiply a whole number to a multiple of \(10\)?
We express the multiple as a product of \(10\) and a number.
Let’s try the following.
Example:
\(5 \times 30 =\) __________
Solution:
We express \(30\) as a product of \(3\) and \(10\).
\(\begin{align*} 5 \times 30 &= 5 \times 3 \times 10 \\ &= 15 \times 10 \\ &= 150 \end{align*}\)
Answer:
\(150\)
Question 1:
Solve the following multiplication.
\(22 \times 10 =\) __________
Answer:
\(220\)
Question 2:
Solve the following multiplication.
\(51 \times 10 =\) __________
Answer:
\(510\)
Question 3:
Solve the following multiplication.
\(38 \times 50 =\) __________
Solution:
\(\begin{align*} 38 \times 50 &= 38 \times 5 \times10 \\ &= 190 \times 10 \\ &= 1900 \end{align*}\) |
Answer:
\(1900\)
Question 4:
Solve the following multiplication.
\(94 \times 50 =\) __________
Solution:
\(\begin{align*} 94 \times 50 &= 94 \times 5 \times 10 \\ &= 470 \times 10 \\ &=4700 \end{align*}\) |
Answer:
\(4700\)
Question 5:
Solve the following multiplication.
\(74 \times 60 =\) __________
Solution:
\(\begin{align*} 74 \times 60 &= 74 \times 6 \times 10\\ &= 444 \times 10\\ &= 4440 \end{align*}\) |
Answer:
\(4440\)
Question 6:
Solve the following multiplication.
\(1059 × 90 =\) __________
Solution:
\(\begin{align*} 1059 \times 90 &= 1059 \times 9 \times 10 \\ &= 9531 \times 10 \\ &= 95 310 \end{align*}\) |
Answer:
\(95 \,310\)
3. Multiplication Of 2-Digit By 2-Digit Numbers
Now, let’s multiply a \(2-\)digit number by a \(2-\)digit number.
Step 1:
We multiply the first number by the digit in the ones place of the second number.
Step 2:
We multiply the first number by the digit in the tens place of the second number.
Step 3:
We add the answers in Step 1 and Step 2.
Question 1:
Solve the following multiplication.
\(18 \times 12 =\) __________
Solution:
Step 1:
Step 2:
Step 3:
Think about this!
You can see \(12 = 10 + 2\).
\(\begin{align*} 18 \times 10 &= 180 \\ 18 \times 2 &= 36 \\ 180 + 36 &= 216 \end{align*}\)
Answer:
\(216\)
Question 2:
Solve the following multiplication.
\(67 \times 38 =\) __________
Solution:
Answer:
\(2546\)
Question 3:
Solve the following multiplication.
\(27 \times 31 =\) __________
Solution:
Answer:
\(837\)
4. Multiplication Of 3-Digit By 2-Digit Numbers
The multiplication of \(3-\)digit numbers by \(2-\)digit numbers is similar to the multiplication of \(2-\)digit numbers by \(2-\)digit numbers.
Step 1:
We multiply the first number by the digit in the ones place of the second number.
Step 2:
We multiply the first number by the digit in the tens place of the second number.
Step 3:
We add the answers in Step 1 and Step 2.
Question 1:
Solve the following multiplication.
\(132 \times 18 =\) __________
Solution:
Step 1:
Step 2:
Step 3:
Think about this!
You can see, \(18 = 10 + 8\).
\(\begin{align*} 132 \times 10 &= 1320 \\ 132 \times 8 &= 1056 \\ 1320 + 1056 &= 2376 \end{align*}\)
Answer:
\(2376 \)
Question 2:
Solve the following multiplication.
\(413 \times 26 =\) __________
Solution:
Answer:
\(10 \,738\)
Question 3:
Solve the following multiplication.
\(634 × 38=\) __________
Solution:
Answer:
\(24 \,092\)
Continue Learning | |
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Multiplication | Whole Numbers |
Multiplication And Division | Decimals |
Model Drawing Strategy | Division |
Fractions | Factors And Multiples |
Area And Perimeter 1 | Line Graphs |
Conversion Of Time |