Page 66 - Start Up Mathematics_4

2. Fill in the blanks.

(a) 63 × 200 = ________ (b) 79 × 600 = ________ (c) 128 × 400 = _______

(d) 268 × 70 = ________ (e) 325 × 90 = ________ (f) 82 × 3,000 = _______

(g) 407 × 5,000 = ________ (h) 650 × 7,000 = ________ (i) 364 × 800 = _______

Multiplication by a 1-Digit Number

Multiplication using standard form
Remember
Example 1: Multiply 3,428 by 9.

Solution: 7 Step 1: Multiply the digit in This method is also known
3 4 2 8 the ones place by 9. as column method.

× 9 8 × 9 = 72

2 Write 2 in the ones place and carry over 7 to the tens
place.
2 7 Step 2: Multiply the digit in the tens place by 9 and add the
3 4 2 8 carried over digit to the product.

× 9 2 × 9 = 18 18 + 7 = 25

5 2 Write 5 in the tens place and carry over 2 to the
hundreds place.
3 2 7 Step 3: Multiply the digit in the hundreds place by 9 and add
3 4 2 8 the carried over digit to the product.
× 9 4 × 9 = 36 36 + 2 = 38

8 5 2 Write 8 in the hundreds place and carry over 3 to the
thousands place.
3 2 7 Step 4: Multiply the digit in the thousands place by 9 and add
3 4 2 8 the carried over digit to the product.
× 9 3 × 9 = 27 27 + 3 = 30

3 0 8 5 2 Write 30 before 852.
So, 3,428 × 9 = 30,852. Remember

Multiplication using expanded form This method is also known

Example 2: Find the product of 325 and 9 using the as row method.
expanded form.
Solution: 325 × 9 = (300 + 20 + 5) × 9 Step 1: Write the multiplicand in
its expanded form.

= (300 × 9) + (20 × 9) + (5 × 9) Step 2: Multiply each term of the
expanded form by the
multiplier.

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