Find the sum of all the 4-digit numbers that can be formed using the digits 4,5,6,7 and 8 without repetition of digits

Mathematics
1

find the sum of all the 4-digit numbers that can be formed using the digits 4,5,6,7 and 8 without repetition of digits

2

Find the sum of all the numbers that can be formed by taking all the digits at a time from 4,5,6,7,8 without repetition.

Sum=10000(4+5+6+7+8)24+1000(4+5+6+7+8)×24+100(4+5+6+7+8)24+
10(4+5+6+7+8)24+1×(4+5+6+7+8)24
=11111(30)24
=7999920

answer: 7999920