0

55 x 81 = (55)·(81) = (50 + 5)·(80 + 1)
= 40x100 + 5x10 + (   )x10 + 5
= 4000 + 50 + (   )x10 + 5 =     4455

0

31

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34

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40

  1 of 50

FirstOuterInnerLast

 

Level

1

2

3

4

How Many

5

10

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30

50

  

FOIL method @

 

Example >>>

 34 x 52 =  (30 + 4)·(50 + 2)

 

 

 

  

First

(A + B)·(C + D) = AC + AD + BC + BD

= 30 x 50

= 1500

Outer

(A + B)·(C + D) = AC + AD + BC + BD

= 30 x 2

=     60

Inner

(A + B)·(C + D) = AC + AD + BC + BD

= 4 x 50

=   200

Last

(A + B)·(C + D) = AC + AD + BC + BD

= 4 x 2

=       8

 

 

    

 

  

 

= 1768