0

209 x 89 = (209)·(89) = (190 + 19)·(80 + 9)
= (   )x100 + 171x10 + 152x10 + 171 =
= (   )x100 + 1710 + 1520 + 171 =     18601

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11

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  1 of 20

FirstOuterInnerLast

 

Level

1

2

3

4

How Many

5

10

20

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