Question

You are given a bag of numbers from 1,2,...,100, and each number appears exactly once. A random number is removed from the bag. How would you calculate the missing number?

Answer 1

there are exactly 100 numbers in the bag,

Answer 2

calculate or guess? To calculate it, assuming I cannot look at the number, I would add the remaining numbers and subtract the total from 5050

Answer 3

why 5050?

Answer 4

\begin{array}l\color{#FF0000}{\text{G}}\color{#FF0000}{\text{ }}\color{#FF7F00}{\text{o}}\color{#FF7F00}{\text{ }}\color{#FFE600}{\text{o}}\color{#FFE600}{\text{ }}\color{#00FF00}{\text{d}}\color{#00FF00}{\text{ }}\color{#0000FF}{\text{ }}\color{#0000FF}{\text{ }}\color{#0000FF}{\text{j}}\color{#0000FF}{\text{ }}\color{#6600FF}{\text{o}}\color{#6600FF}{\text{ }}\color{#8B00FF}{\text{b}}\color{#8B00FF}{\text{ }}\color{#FF0000}{\text{!}}\color{#FF0000}{\text{ }}\end{array}

Answer 5

haha

Answer 6

5050 is the sum of numbers from 1 to 100. If he adds up the remaining numbers in the bag, the difference between 5050 and what he gets after adding up the number is equal to the number that is missing from the bag.