# Mentally Multiply by 5, 25, 50, 250

This is a simple quicker math trick but it can be very useful for young students to solve seemingly difficult calculations. I will be glad to get your feedback on this.

### Mental multiplication by 5, 25, 50, 250, 500 and so on.

Any number can be expressed in different ways. For example, 5 can be expressed as 10x(1/2).

**Trick: Multiplication by 5**

Step 1: Multiply the number by 10, i.e. simply place a zero after the number.

Step 2: Halve the resultant number.

**Example 1: **

5 × 136 = ten times of 136 i.e. 1360 should be divided by 2 = 1360/2 = 680

**Example 2:**

5 × 343, half of 3430 is 1715

Also check out, how to mentally multiply by 111?

**Trick: Multiplication by 50, 500, 5000 and so on..**

The above logic can also be applied to 50 which is half of 100 i.e. 1/2×100

Instead of multiplying the number by 10 we have to multiply by 100. So we have to place two zeroes after the number.

**Example 1: **

50 × 136 = hundred times of 136 i.e. 13600 should be divided by 2 = 13600/2 = 6800

**Example 2: **

50 × 647 = hundred times of 647 i.e. 64700 should be divided by 2 = 64700/2 = 32350

Same logic can be extended to numbers like 500, 5000 and so on.

**Trick: Multiplication by 25**

For multiplication by 25, we have to go one step further, 25=100 x (1/2) x (1/2)

Step 1: Multiply the number by 100, i.e. simply place two zeroes after the number.

Step 2: Halve the resultant number.

Step 3: Again halve the resultant number.

**Example 1: **

25 × 136 = hundred times of 136 i.e. 13600 should be divided by 2 = 13600/2 = 6800. Again halve this number, 6800/2 = 3400

**Example 2:**

25 × 343, half of 34300 is 17150. Again half of 17150 is 8575.

The above logic can also be extended to numbers like 250, 2500 and so on.

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thank u sir,, great short cuts,,, it saves a time a lot

thank u sir.. its a wonder short cuts.. very useful to me

thanks for all this

* if u want to multiply 25 with any no just put double zero and devide by 4

25*12 —–1200/4 = 300

25*444 44400/4 =11100

thanks a lot for this shortcut method of multiplication its really usefull to me

wonderfull work thanks a lot;)

You are really HEROES,KEEP IT UP,thanks

hello sir can u explain how to guess the aproximate ans in complex caliculations like

939202/34572

dnt use shortcuts for these type of multiplication….

use calc

try to divide 939 by 34,will lead approximate value

great work buuddyyy.

you r excellent and mind blowing and how do you get these

Thanks……. u give a seriously mind-blowing methods to solve numerical in a very easy way

Thanks to all of you 🙂

its really gr8…:)

gud one 🙂

Thank you