Multiplying 2 numbers close to 100
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Transcript of Multiplying 2 numbers close to 100
Coffee Math:
Methods, Tips And Tricks Series.
By Puwork UtaraMay 2011
Multiplying 2 Numbers
Close to 100
They are in the base 100. Hence the reference point
(base) will be 100.
88 98 = ______X
Both numbers
are close to 100
but less than 100
88 98 = ______X
88
98
100
100
+12
+ 2
88 98 = ______X
88
98
100
100
+12
+ 2
88 - 2( ) 100X = 8600Either
98 - 12( ) 100X = 8600Or
88 98 = ______X
88
98
100
100
+12
+ 2
88 - 2( ) 100X = 8600Either
98 - 12( ) 100X = 8600Or
12 2X = 24And
88 98 = ______X
88
98
100
100
+12
+ 2
88 - 2( ) 100X = 8600Either
98 - 12( ) 100X = 8600Or
12 2X = 24And
+ =24Last 8600 8624 #
102 104 = ______X
Both numbers
are close to 100
but more than 100
102 104 = ______X
102
104
100
100
- 2
- 4
102 104 = ______X
102
104
100
100
- 2
- 4
102 + 4( ) 100X = 10600Either
104 + 2( ) 100X = 10600Or
102 104 = ______X
102
104
100
100
- 2
- 4
102 + 4( ) 100X = 10600Either
104 + 2( ) 100X = 10600Or
-2 -4X = + 08And
102 104 = ______X
102
104
100
100
- 2
- 4
102 + 4( ) 100X = 10600Either
104 + 2( ) 100X = 10600Or
-2 -4X = + 08And
+ =(+08)Last 10600 10608 #
97 102 = ______X
One of the numbers
is less than 100 and
the second number
is more than 100
97 102 = ______X
97
102
100
100
+ 3
- 2
97 102 = ______X
97
102
100
100
+ 3
- 2
97 - ( -2)( ) 100X = 9900Either
104 - 3( ) 100X = 9900Or
97 102 = ______X
97
102
100
100
+ 3
- 2
97 + 2( ) 100X = 9900Either
104 - 3( ) 100X = 9900Or
+ 3 (-2 )X = - 06And
97 102 = ______X
97
102
100
100
+ 3
- 2
97 + 2( ) 100X = 9900Either
104 - 3( ) 100X = 9900Or
+ 3 (-2 )X = - 06And
+ =(- 06 )Last 10600 9894 #
END
