Question

prove 1⁹⁹+ 2⁹⁹+3⁹⁹+ 5⁹⁹ is divisible by 5​

Answer 1

Answer:1^99 unit digit is 1

2^99 unit digit is 8

3^99 unit digit is 7

5^99 unit digit is 5

1+8+7+5=20

So if the last digit is 0 or 5 then it is divisible by 5

Step-by-step explanation: