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How do i solve this question

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Re: How do i solve this question

by jimbow » Mon Oct 22, 2007 4:50 am
HELP ME wrote:What will be the number in the units position for the following number.

(13)^4 * (17)^2 * (29)^3

how do i solve this in under 1 minute and half ???

im confused ??
13x13x13x13 => 3x3=9; 9x3= 27; 7x3 =21

17x17 => 7x7 = 49

29x29x29 => 9x9= 81; 1x9 = 9

1x49x9= ..1

Unit number is 1
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by jangojess » Mon Oct 22, 2007 5:42 am
to solve Qs like these you need to know the pattern of powers of numbers from 1 to 9...powers from 1 to 10 would suffice to solve Qs like these and then some properties related can help u...

One property that I can tell u is a digit when raised to a power of 5 will have the same number repeated in the unit digit...
eg: 2^5 = 32...has 2 in unit digits, 3^5 = 243...has 3 in unit digits, 9^5 = 59049...has 9 in units digit.

So try to see the units digit pattern for Qs like these. A quick multiplication of digits can save a lotta time too
Trying hard!!!
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