How much is 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 added to 100

How much is 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 added to 100

Add 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 to 100
=(1+100)*100/2=5050