Question

What is the remainder when 1! + 2! + 3! + ... + 100! Is divided by 5?​

Answer 1

Answer:

Notice that from 5! onwards all the numbers up till 100! are multiples of 5, i.e., they have at least one factor of 5. Like; 5!=120,6!=720, etc.

So we basically have to find the remainder of 1!+2!+3!+4! .

Now, 1!=1,2!=2,3!=6,4!=24

Adding, we get 33, which everybody knows , leaves a remainder of 3 when divided by 5.

Hence, Ans.=3

Answer 2

Answer:

1010 there is no remainder!!

Step-by-step explanation:

1+2+3+4...…..+99+100 = 5050

5050 divided by 5 = 1010