Example ( 1 ):

)1 2 ( 2=

- - -

1 2 + 2 = 14 ، 2 x 2 = 4

1 4 4

Example ( 2 ):

)1 3 ( 2=

- - -1 3 + 3 = 16 ، 3 x 3 = 9

1 6 9

Example ( 3 ):

)1 4 ( 2=

- - -1 4 + 4 = 18 ، 4 x 4 = 16

1 9 6

Example ( 4 ):

)1 5 ( 2=

- - -1 5 + 5 = 20 ، 5 x 5 = 25

2 2 5

Square a Number مربعات األعداد

Example ( 1 ):

)35 ( 2=

- - - -

3 x 4 = 12 ، 5 x 5 = 25

1225

Example ( 2 ):

)75 ( 2=

- - - -7 x 8 = 56 ، 5 x 5 = 25

5625

Example ( 3 ):

)125 ( 2=

- - - -1 2 x 1 3 = 156 ، 5 x 5 = 25

15625

Example ( 4 ):

)15 ( 2=

- - - -1 x 2 = 2 ، 5 x 5 = 25

225

Example ( 1 ):

1 3 x 1 3=

1 -square the first number 1 x 1 = 1

2 -square 3 in the 13 3 x 3 = 9

3 -know take 1x 3 = 3+3 (double)= 61 6 9

Example ( 2 ):

7 2 x 7 2=

1 -square the first number 7 x 7 = 492 -square 2 in the 72 2 x 2 = 4

3 -know take 7x 2 = 14+14 (double)= 28

4928

4

5184

Example ( 3 ):

6 3 x 6 3=

1 -square the first number 6 x 6 = 362 -square 3 in the 63 3 x 3 = 9

3 -know take 6x 3 = 18+18(double)= 36

3636

9

3969

Example ( 4):

5 4 x 5 4=

1 -square the first number 5 x 5 = 252 -square 3 in the 54 4 x 4 = 16

3 -know take 5x 4 = 20+20(double)= 40

2540

16

2916

Example ( 1 ):

)95 ( 2=

- - - -

95 - 5 = 90 ، 5 x 5 = 25

9025

Example ( 2 ):

)96 ( 2=

- - - -96 - 4 = 92 ، 4 x 4 = 16

9216

Example ( 3 ):

)85 ( 2=

- - - -85 - 15 = 70 ، 15 x 15 = 225

7225

Example ( 4 ):

)88 ( 2=

- - - -88 - 12 = 76 ، 12 x 12 = 144

7744

Example ( 1 ):

)32 ( 2=

- - - - )30 + 2 ( 2 =

Example ( 2 ):

Example ( 3 ): )5 1 ( 2=

- - -

)30( 2 = 9002 x 30 x 2 = 120 )2( 2 = 4

1024

)74 ( 2=

- - - - )70 + 4 ( 2 =

)70( 2 = 4900

2 x 70 x 4 = 560 )4( 2 = 16

5476

)50( 2 = 25002 x 50 x 1 = 100 )1( 2 = 1

2601

)a 5 ( 2=

- - -

a2 + a = - - - ، 5 x 5 = 25

---25

Example ( 1 ):

)35 ( 2=

- - -32 + 3 = 12 ، 5 x 5 = 25

1225

Example ( 2 ):

)45 ( 2=

- - -42 + 4 = 20 ، 5 x 5 = 25

2025

Example ( 3 ):

)65 ( 2=

- - -62 + 6 = 42 ، 5 x 5 = 25

4225

Example ( 1 ):

)48 ( 2=

- - -

Example ( 2 ):

Example ( 3 ):

Example ( 4 ):

Smarter way to square any number between 30 - 70

2 less than 5025 – 2 = 23

square 2 = 4

2304

2304

)46 ( 2= 4 less than 50

25 – 4 = 21square 4 = 16

2116

2116

)37 (2=

- - -

- - -13 less than 50

25 – 13 = 12square 13 = 169

12169

1369

)40 (2=

- - -10 less than 50

25 – 10 = 15

square 10 = 100،15

100

1600

Example ( 5 ):

)52 ( 2=

- - -

Example ( 6 ):

Example ( 7 ):

Example ( 8 ):

2 much more than 5025 + 2 = 27

square 2 = 4

2704

2704

)57 ( 2= 7 much more than 50

25 + 7 = 32square 7 = 49

3249

3249

)60 ( 2=

- - -

- - -10 much more than 50

25 + 10 = 35square 10 = 100

35100

3600

)65 ( 2=

- - -15 much more than 50

25 + 15 = 40

square 15 = 225، 40225

4225

Multiplying a number less than 100 by 99

99 x 98=

- - - -

98 - 1 = 97 ، 100 - 98= 02

9702

Example ( 2 ):

99 x 47=

- - - -47 - 1 = 46 ، 100 - 47= 53

4653

Example ( 3 ):

99 x 4=

- - - -4 - 1 = 03 ، 100 - 4= 96

0396

Example ( 4 ):

99 x 17=

- - - -17 - 1 = 16 ، 100 - 17= 83

1683

Example ( 1 ):

Multiplying a number less than 100

Example ( 2 ):

،

Example ( 3 ):

،

Example ( 4 ):

،

Example ( 1 ):

-2 -3 97 – 2 = 95 ، 2 x 3 = 6

9506

93 x 92 - - - - =

98 x 97- - - - =

-7 -8 93 – 8 = 85 7 x 8 = 56

8556

87 x 91 - - - - =

-13 -991 – 13 = 78 13 x 9 = 117

7917

30 x 20 - - - - =

-70 -8030 – 80 = -50 70 x 80 = 5600 5600

-50

600

،

Multiplying a number between 11 to 19

Example ( 2 ):

Example ( 3 ):

Example ( 4 ):

Example ( 1 ):

13 x 12 = 156+

x

19 x 15 = 145+

x

1 4= 285

11 x 11 = 121+

x

17 x 13 = 101+

x

1 2= 221

Example ( 5 ):

12 x 15 = 170+

x

1= 180

Example ( 6 ):

18 x 19 = 172+

x

1 7= 342

Example ( 7 ):

12 x 12 = 144+

x

Example ( 4 ):

14 x 13 = 172+

x

1= 182

Example ( 1 ):

3563 x 11- - - - =

Example ( 2 ):

Example ( 3 ):

How to multiply any number by 11

Copy the first digit 33 + 5 = 8

5 + 6 = 116 + 3 = 9

At the end copy the last digit 3

3811

93

39193

4216 x 11- - - - = Copy the first digit 4

4 + 2 = 62 + 1 = 31 + 6 = 7

At the end copy the last digit 6

46

37

6

46376

21432 x 11- - - - = Copy the first digit 2

2 + 1 = 31 + 4 = 54 + 3 = 73 + 2 = 5

At the end copy the last digit 2

23

57

52

235752

Example ( 1 ): 1332 x 12- - - - =

Example ( 2 ):

Example ( 3 ):

How to multiply any number by 12

Copy the first digit 1Double ( 1 ) + 3 = 5

Double the last digit ( 2 ) 4

Double ( 3 ) + 3 = 9 Double ( 3 ) + 2 = 8

15

98

4

15984

3563 x 12- - - - = Copy the first digit 3

Double ( 3 ) + 5 = 11 Double ( 5 ) + 6 = 16Double ( 6 ) + 3 = 15Double the last digit ( 3 ) 6

4216 x 12- - - - = Copy the first digit 4

Double ( 4 ) + 2 = 10 Double ( 2 ) + 1 = 5Double ( 1 ) + 6 = 8Double the last digit ( 6 ) 12

311

1615

6

42756

410

5812

50592

Example ( 1 ): 1332 x 13- - - - =

Example ( 2 ):

Example ( 3 ):

How to multiply any number by 13

Copy the first digit 1Triple ( 1 ) + 3 = 3 + 3 = 6

Triple the last digit ( 2 ) 6

Triple ( 3 ) + 3 = 9 + 3 = 12Triple ( 3 ) + 2 = 9 + 2 = 11

1612

116

17316

12231 x 13- - - - = Copy the first digit 1

3

Triple ( 1 ) + 2 = 3 + 2 = 5 Triple ( 2 ) + 2 = 6 + 2 = 8Triple ( 2 ) + 3 = 6 + 3 = 9Triple ( 3 ) + 1 = 9 + 1 = 10

Triple the last digit ( 1 )

15

8910

3

159003

111 x 13- - - - = Copy the first digit 1

Triple ( 1 ) + 1 = 3 + 1 = 4Triple ( 1 ) + 1 = 3 + 1 = 4

Triple the last digit ( 1 ) 3

14

43

1443

Multiplying using base 10

8 x 7=

- -

،

Example ( 2 ):

،

Example ( 3 ):

Example ( 4 ):

Example ( 1 ):

-2 -3

7 – 2 = 5 2 x 3 = 6

5 6

8 – 3 = 5 2 x 3 = 6

5 6

9 x 6=

- - 9 – 4 = 5

-1 -41 x 4 = 4

5 4

6 – 1 = 5 1 x 4 = 4

5 4

7 x 4=

- -

-3 -6

4 – 3 = 1 3 x 6 = 1 8

2 8

7 – 6 = 1 3 x 6 = 1 8

2 8

2 x 3=

- -

،

-8 -7

2 – 7 - = 58 x 7= 56

6

،3 – 8= -58 x 7= 56

6

Example ( 1 ):

Example ( 2 ):

Example ( 3 ):

How to multiply a number by 5

36 x 5 =

x 5 =

Example ( 4 ):

x 5 =

The trick is: divide by 2 Multiply by 10 = - - -

24 x 5 =

24 ÷

÷

÷

÷

÷

2 =

=

=

=

=

12 12 x 10 = 120

36 2 18 18 x 10 = 180

12

12 2 6 6 x 10 = 60

1515 2 7.5 7.5 x 10 = 75

Example ( 5 ): 18 x 5

18 2 = 9 9 x 10 = 90

Example ( 1 ):

Example ( 2 ):

Example ( 3 ):

Example ( 4 ):

Divide a number by 5

24 ÷ 5 =

24 + 24 = 48 4 . 8

36 ÷ 5 =36 + 36 = 72 7 . 2

12 ÷ 5 =12 + 12 = 24 2 . 4

73 ÷ 5 =73 + 73 = 146 14 . 6

Example ( 5 ):

67 ÷ 5 =67 + 67 = 134 13 . 4

Convert from Centigrade to Fahrenheit

Example ( 2 ):

Example ( 3 ):

Example ( 1 ):

22 ° C °F - - -

22 + 22 = 44

44 + 30 = 74

22 ° C °F74

32 ° C °F- - -

32 + 32 = 64

64 + 30 = 94

32 ° C 94 °F

19 ° C - - - °F19 + 19 = 38

38 + 30 = 68

19 ° C °F68