Here is shortcut for multiplying a number with last digit 1 or 9. This shortcut is most applicable for 2 or 3 digit numbers. Shortcut tricks are very helpful in competitive exams as time allotted is too less for lengthy calculations. So shortcut tricks helps us to solve questions is very less time.
Shortcut for Multiplying a Number Ending with 1
To multiply a number ending with 1, we can split it in multiple of 10 + 1. Follow examples below to understand how to multiply:
Eg. 1:
43 * 61
= 43 * (60+1)
= 43 * 60 + 43
= 2580 + 43
= 2623
Eg. 2:
65 * 21
= 65 * (20+1)
= 65 * 20 +65
= 1300 +65
= 1365
Try yourself:
- 41 * 27 =
- 38 * 21 =
- 88 * 51 =
- 31 * 17 =
- 64 * 21 =
Shortcut for Multiplying a Number Ending with 9
To multiply a number ending with 9, we can splitl it into multiple of 10 - 1. Follow examples below to understand how to multiply:
Eg. 1:
43 * 29
= 43 * (30 - 1)
= 43 * 30 - 43
= 1290 - 43
= 1247
Eg. 2:
24 *19
= 24 * (20 - 1)
= 24 * 20 -24
= 480 - 24
= 456
Try yourself:
- 64 * 49 =
- 39 * 23 =
- 17 * 99 =
- 62 * 19 =
- 34 * 69 =
Mathematics is all about practice. Practice more and more problems of this type to improve your speed.
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