Please help me solve this question How many 4 digits number with all digits different are tbere between 1000 and 9999 such tbat the difference between the first and the last digit is plus or ninus 3.


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Question Number 49930 by OTCHRRE ABDULLAI last updated on 12/Dec/18

$P l e a s e h e l p m e s o l v e t h i s q u e s t i o n$ $H o w m a n y 4 d i g i t s n u m b e r w i t h a l l d i g i t s$ $d i f f e r e n t a r e t b e r e b e t w e e n 1000 a n d 9999$ $s u c h t b a t t h e d i f f e r e n c e b e t w e e n t h e f i r s t$ $a n d t h e l a s t d i g i t i s p l u s o r n i n u s 3 .$
	Answered by mr W last updated on 12/Dec/18

	$n u m b e r p a i r s w i t h d i f f e r e n c e 3 :$ $0 / 3, 1 / 4, 2 / 5, . . ., 6 / 9 \Rightarrow 7 p a i r s$ $(2 \times 7 - 1) \times 8 \times 7 = 13 \times 8 \times 7 = 728$ $\Rightarrow 728 s u c h n u m b e r s .$ $- 1 b e c a u s e n u m b e r s s t a r t i n g w i t h 0$ $m u s t b e r e m o v e d .$
	Commented by OTCHRRE ABDULLAI last updated on 12/Dec/18

	$G o d r i c h l y b l e s s y o u M r . w f o r y o u r$ $h e l p a m m u c h g r e a t f u l$
	Commented by mr W last updated on 12/Dec/18

	$t h a n k y o u s i r!$
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