what is the units digit of 26 ! + 50 ! + 4 ! + 4 ! ?
"let us first write down the factorials of different numbers : 1 ! = 1 2 ! = 2 3 ! = 6 4 ! = 24 5 ! = 120 6 ! = 720 and so on . if we notice here , all the numbers after 4 ! will end with a 0 . here is why : if we multiply any number by 10 , a 0 is added to that number and a 10 is formed by a 5 and a 2 , 10 = 5 * 2 till 4 ! , we do not have a ` ` 5 ' ' in multiplication . but after that , we will have atleast one ` ` 5 ' ' in the multiplication . coming back to the question , units digit of 26 ! + 50 ! + 4 ! + 4 ! = ? by the logic above , 26 ! and 50 ! will end in a ` ` 0 ' ' 4 ! will end in a 4 hence the units digit = 0 + 0 + 4 + 4 = 8 correct option : a"
add(add(const_4, const_3), const_2)