Mathematics Made Easy: Doubling
Any Number
H.D.
Motiramani
Doubling
any number means multiplying it by 2. We will also get the same result if we
add the same number to it. For example double of 42 is
42×2=84 or 42+42=84. Let us see the examples of Doubling Sums below in a
tabular form.
|
Number |
Double
of the number |
|
36 |
36 + 36 = 35+35+1+1
= 70+2 Or
35×2+1×2 = 70+2 =72 Doubling any number ending with 5 or 0 is easy. |
|
57 |
57+57 = 55+ 55
+ 2 + 2 = 110+4
= 114 |
|
626 |
626 +
626= 600+20+6 and the double of this : = 1200 +
40 + 12 = 1252 626=600+20+6. Therefore double of this is 1200+40+12=1252 |
|
4278 |
4278 +
4278 = (4200
+ 4200) + (70+70) + (8+8) = 8400
+140 + 16 = 8556 |
|
794856 |
For
Larger numbers we can achieve the result by Break & double 79
║ 48 ║ 5 6 = 158║9 6║112 =
158║97║12 Answer : 1589752 794856 was broken into 3 parts 79,48 and 56. It is to be noted that the double of two digits in any segment
other than the leftmost segment has to be in two digits only and if the
double happens to come in 3 digits Like 112 in right most segment the unit
digit is to be carried over to its left and added there. (Likewise if there
was broken a number in a single digit segment and the result of doubling
comes in two digits, its result will be kept in single digit in that part of
the break and the left most digit will be carried over to its left
segment.) |
|
58554 |
Another
example of break and double 58553
= 58║55║3 =
116║110║6 = 117║10║6 =
117106 110 in middle segment has to be in two digits only. Therefore only 10 kept there and 1 carried over to its
left and added there. |
|
79865462 |
Breaking
any long number in all single digit segments 79865462 = 7 ║ 9 ║ 8 ║ 6
║ 5 ║4║ 6 ║2 *Double
of this = 14║18║16 ║12 ║10 ║8 ║12║4 Answer =
15║ 9║ 7║ 3
║ 0 ║9 ║ 2 ║4 Answer
=159730924 *All the numbers in all segments except left most have to be in
single digit. Therefore moving from right to
left, leave the unit digit in that segment and carry the other digit to its
leftsegment. |
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