try it

What is the digit in the unit's place of
1!+ 2! + 3!+...... + 99!

2 Answers

observe that all terms after 4! (starting from 5!)

have a 5*2 =10 in them .. thus they will all end in zeros and thus would not contribute to the sum

so just sum up the first four !
1+2+6+24=33

thus 3

easy 1 .. its 3.. after 5! it will b 0,,sum 1st 4 like above dude has done..

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