math

posted by .

sabrina used a calcutator and started adding the whole numbers in order 1+2+3+4+5+..... what is the last number she would add that would get the sum on her calculator over 1000?

Try it yourself. You'll be surprised that it won't take very long to add up to 1,000.

To find the sum of the numbers from 1 to "n":
(1+n)(n/2)=sum
1001=(n^2+1)/2
2002=n^2+1
2001=n^2
n=44.7.....
So, 45 is the last number she would add.

• math -

995

Similar Questions

1. math

You have 2 digits, 2 numbers, reverse digits and 54 if the difference and the sum of all is 10 I'm not clear what you're asking, could you clarify what the conditions are for us please?
2. conjectures

Evaluate the following sums: 1 1+8 1+8+27 1+8+27+64 Add two more line to the list, and make a conjecture about the sums you obtained. this is a pattern. if you look closely than you'll see each number is a product of another number …
3. algebra

please write an explaination why (x^3)(x^4) is not x^12. I am confused thank you. it is not the answer because, first of all, try replacing x with another number, in this case, let's say two. (2^3)(2^4)= 128, and if you try 2^12, you …
4. maths

the sum of N positive integers is 19. what is the maximum possible product of these N numbers?
5. College Algebra

The sum of two numbers is less than 12. The second number is 8 more than the first. What are the possible values for the first of the two numbers?
6. Math

The product of 1000 whole numbers is 1000. What is the largest possible value the sum of these numbers can have?
7. Math

10.Mr. Cartwright bought 2 7/8 pounds of grapes for his lunches. If he paid \$1.79 for each pound about how much did he pay for grapes?
8. math

the product of 1000 whole number is 1000, what is the largest possible value the sum of these numbers can have