Page 211 - Start Up Mathematics_5

Vedic Mathematics

Multiplying numbers not close to 100
Let’s multiply 21 by 23.
2 1
Step 1: Multiply the digits in the ones place and × 2 3
write the product.
3
2 1
Step 2: Cross-multiply and add the product. Place
it to the left of the number in step 1. × 2 3 (6 + 2 = 8)
8 3
Step 3: Multiply the digits in the tens place and 2 1
write it to the left of the number in step 2.
× 2 3
4 8 3
21 × 23 = 483
Now let’s try 23 × 27.
2 7
Step 1: Multiply the digits in the ones place and write the product. Carry × 2 3
forward the tens digit of the product.
2 3 2 1
Step 2: Cross-multiply and add the product. Place it to the left of the number × 2 7 14 + 6 = 20
2
in step 1. Add the carried-forward digit in step 1 to it and again carry 2 1 20 + 2 = 22
forward the tens digit.
2 7
Step 3: Multiply the digits in the tens place and write the product to the left × 2 3
of the number in step 2. Add the carried forward number to it and get 2
the answer. 4 2 1
6 2 1
Multiplying numbers close to 100
Let’s multiply 86 by 97. 1 0 0 1 0 0
– 8 6 – 9 7
Step 1: Subtract both numbers from 100. 1 4 3

Step 2: Multiply the differences and write the product. 1 4
× 3
4 2 8 6 – 3

Step 3: Subtract the difference of any one number obtained in step 1 from the OR → = 83
other number. 9 7 – 1 4

Step 4: Place this number to the left of the number in step 2.

86 × 97 = 8,342

These magic tricks can be applied to decimals as well. Practise and you will be amazed to see your speed of
calculation.

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