I have a math question which am facing a problem in it?

Eshita is incorrect, she gave you the amount of odd numbers between 1 and 199, but did not give you the SUM of all of them, which would be adding them all together. im not sure what the variable in the equation are, but it is the equivalent of adding all of the odd numbers 1+3+5+6......+103+105+107 etc etc. i hope this helps