# Math

How to calculate 1+2+3+...+99+100 without a calculator?

1. 👍 0
2. 👎 0
3. 👁 171
1. 1+2+3+...+99+100
form pairs in the following way:
= (1+100) + (2+99) + (3+98) + ....
= 101 + 101 + 101 + ...
how many 101's will you have ?

Legend has it that the famous German mathematician Gauss, did this in his head when his teacher assigned it in early grade school as "busy work" to keep the kids quiet.

1. 👍 0
2. 👎 0
2. Thank you!

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Logs

Approximate e^-0.6 to 3 decimal places. I am not sure how to approach this without a calculator. I don't think we are allowed to use a calculator but I'm not 100% sure on that either.

2. ### Mathematics

Year Annual CPI Actual Price of a Calculator 1995 152.400 \$8.99 2000 172.200 \$10.49 2005 195.300 \$12.10 2010 218.056 \$12.75 2015 237.017 \$13.89 Based on inflation from the year 1995, calculate the expected price of a calculator

3. ### chemistry

Calculate the change in pH when 9.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq). Calculate the change in pH when 9.00 mL of 0.100 M NaOH(aq) is added to the

4. ### chemistry

Calculate the H3O+ concentration present in water under the following conditions. Enter your answer in scientific notation. a. [OH-] = 2.8 x 10-7 M b. [OH-] = 8.8 x 10-3 M c. [OH-] = 2.4 x 10-11 M everytime I do the problem In the

1. ### statistics

A professional basketball player has embarked on a program to study his ability to shoot foul shots. On each day in which a game is not scheduled, he intends to shoot 100 foul shots. He maintains records over a period of 40 days

2. ### Algebra

My calculator is broken. The "+" key works correctly,but whenever I try to compute a-b, the calculator performs b-a instead. What answer does mny calculator compute for the expression ((7-10)+3)-5? Thank you!

3. ### Algebra

A school planned to buy x calculators for a total cost of Ksh 16200. The supplier agreed to offer a discount of Ksh 60 per calculator. The school was the able to get three extra calculators for the same amount of money. (a) Write

4. ### College Algebra

A calculator company produces a scientific calculator and a graphing calculator. Long-term projections indicate an expected demand of at least 100 scientific and 80 graphing calculators each day. Because of limitations on

1.evaluate without using a calculator 2logx+1=log900 2.solve the following equation A. 3log(x-2)=4.714 B. 16^x-3 = 8^2x+1 C.10^2x=1/100

2. ### Mathematics concepts

Matthew sits at his desk unable to figure out the answer to a division problem. He reaches into his desk and pulls out a calculator. What is the correct response for Matthew's teacher to have? A. "Put that calculator away, you

3. ### Trigonometry college

Use a calculator to solve csc (theta) = -3. I know the answer is 3.48 and 5.94 but I need the steps to take on the calculator to arrive at the answer. I have a ti-84 calculator. thanks!

4. ### math

belinda used her calculator to find the decimal for the fraction 21/28.When she entered 21/28, the calculator gave an answer that looked familiar. Why do you think she recognized it?