MULTIPLICATION TRICKS

To understand multiplication tricks, you have to remember the following multiplication.  

"Single digit number x Single digit number"

Example:

6 x 7  =  42 

8 x 9  =  72

4 x 9  =  36

And it is difficult for us to remember answer for

"Two digit number x Single digit number"

and 

"Two digit number x Two digit number"

Here, we have given shortcuts to find answer for the above multiplications which come in times table.

Two Digit Number x Single Digit Number

This method is explained for 1 at the ten's place of two digit number (Times Table).

Steps to be followed to understand the above shortcut :

Step 1 :

First take the single digit number and multiply it by 10. 

    (7 x 10  =  70 in the above example)    

Step 2 :

Multiply the single digit and unit digit of the two digit number    

 (7 x 2  =  14  in the above example)

Step 3 :

Add step 1 value and step 2 value.

(70 + 14  =  84 in the above example)

That's it.

Try yourself :

14 x 8  =  ?

19 x 8  =  ?

7 x 18  =  ?

In this way you can try a lot.

Any Two Digit Number x Single Digit Number

Steps to be followed to understand the above shortcut :

Step 1 :

First take the digit at ten's place of two digit number and multiply it by the given single digit number. 

    (2 x 7  =  14 in the above example)    

Step 2 :

Add "zero" at the end of step1 value.     

 (14 -----> 140  in the above example)

Step 3 :

Multiply the unit digit of two digit number and the given single digit number.

(4 x 7  =  28  in the above example)

Step 4 :

Add step 2 and step 3 values and you will get the answer.

(140 + 28  =  168  in the above example)

That's it.

Try yourself :

34 x 8  =  ?

49 x 7  =  ?

67 x 4  =  ?

In this way you can try a lot.

Two digit number x Two digit number

This method is explained for "1" at the ten's place of both the two digit numbers (Times Table)

Method 1 :

Method 2 :

Steps to be followed to understand both the methods :

Step 1 :

First take one of the two digit numbers and multiply it by 10.

Step 2 :

Multiply the unit digit of other two digit number by 10.

Step 3 :

Multiply unit digits of both the numbers.

Step 4 :

Add all the above three values and you will get answer.

That's it

Try yourself :

17 x 18  =  ?

18 x 19  =  ?

15 x 19  =  ?

In this way, you can try a lot.

Beware!

To use these shortcuts, you must have much practice on these. Otherwise, the shortcuts explained above will not work properly and you may not be able to get correct answer. So, please do much practice on these shortcuts using different numbers. 

One more caution on these shortcuts :

We can take only 1 at the ten's place of two digit numbers and not any number.

Practice Problems

Problem 1 : 

Evaluate : 

297 x 5

Solution : 

297 x 5  =  (300 - 3) x 5

297 x 5  =  1500 - 15

297 x 5  =  1485

Problem 2 : 

Evaluate : 

30 x 25

Solution : 

30 x 25  =  30 x (20 + 5)

30 x 25  =  600 + 150

30 x 25  =  750

Problem 3 : 

Evaluate : 

1250 x 6

Solution : 

1250 x 6  =  (1000 + 250) x 6

1250 x 6  =  6000 + 1500

1250 x 6  =  7500

Problem 4 : 

Evaluate : 

1500 x 12

Solution : 

1500 x 12  =  1500 x (10 + 2)

1500 x 12  =  15000 + 3000

1500 x 12  =  18000

Problem 5 : 

Evaluate : 

500 x 16

Solution : 

500 x 16  =  500 x (10 + 6)

500 x 16  =  5000 + 3000

500 x 16  =  8000

Apart from the stuff given above, if you need any other stuff, please use our google custom search here. 

You can also visit the following web pages on different stuff in math. 

WORD PROBLEMS

HCF and LCM  word problems

Word problems on simple equations 

Word problems on linear equations 

Word problems on quadratic equations

Algebra word problems

Word problems on trains

Area and perimeter word problems

Word problems on direct variation and inverse variation 

Word problems on unit price

Word problems on unit rate 

Word problems on comparing rates

Converting customary units word problems 

Converting metric units word problems

Word problems on simple interest

Word problems on compound interest

Word problems on types of angles 

Complementary and supplementary angles word problems

Double facts word problems

Trigonometry word problems

Percentage word problems 

Profit and loss word problems 

Markup and markdown word problems 

Decimal word problems

Word problems on fractions

Word problems on mixed fractrions

One step equation word problems

Linear inequalities word problems

Ratio and proportion word problems

Time and work word problems

Word problems on sets and venn diagrams

Word problems on ages

Pythagorean theorem word problems

Percent of a number word problems

Word problems on constant speed

Word problems on average speed 

Word problems on sum of the angles of a triangle is 180 degree

OTHER TOPICS 

Profit and loss shortcuts

Percentage shortcuts

Times table shortcuts

Time, speed and distance shortcuts

Ratio and proportion shortcuts

Domain and range of rational functions

Domain and range of rational functions with holes

Graphing rational functions

Graphing rational functions with holes

Converting repeating decimals in to fractions

Decimal representation of rational numbers

Finding square root using long division

L.C.M method to solve time and work problems

Translating the word problems in to algebraic expressions

Remainder when 2 power 256 is divided by 17

Remainder when 17 power 23 is divided by 16

Sum of all three digit numbers divisible by 6

Sum of all three digit numbers divisible by 7

Sum of all three digit numbers divisible by 8

Sum of all three digit numbers formed using 1, 3, 4

Sum of all three four digit numbers formed with non zero digits

Sum of all three four digit numbers formed using 0, 1, 2, 3

Sum of all three four digit numbers formed using 1, 2, 5, 6