Math Problem (Level 1) : Number added to be over 1000 of the sum (A1)

A number is added in an order from 1 as 1 + 2 + 3 + ------. 

When a certain number was added, the sum exceeded 1000 for the first time. 

Find both of the number and the sum. 




Answer
Number is 45, 
sum is 1035