# Tag Archives: Sum

## Use digits 1,9,8,2 and basic operations to make 0-100

Use the basic operations (+, -, x, /, √, ||) ||   stands for concatenation.     Please extend the list.                       Advertisements

## Puzzle | 4 items in a store; a*b*c*d = a+b+c+d

PART 1   The price tags on three items in a store are : We note that Find four prices,   a,   b,   c,   and   d   such that   Paul and David answered correctly … Continue reading

Posted in Number Puzzles | Tagged , | 1 Comment

## Sum of consecutive odd numbers

Parity http://mathworld.wolfram.com/Parity.html   Let     be a positive integer and     be any integer with the same parity as   with   These odd integers are all positive.   for example, If   n = 2,    … Continue reading

## Pattern | Sum of all positive integers (multiples of 2 and 5 excluded)

multiples of 2 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, … multiples of 5 5, 10, 15, 20, 25, 30, …   Let’s take the sum of all positive integers which … Continue reading

## (n, n+1) Higher Sum and Product

Among the distinct pairs of numbers whose sum is   ,   the greatest possible product is   Consider   ,   find the distinct ways of achieving a higher product with two positive integers   Here are the … Continue reading

## 1/a^2 + 1/b^2 + … + 1/x^2 = 1/2

The equation 1/a^2   +   1/b^2   +   1/c^2   + … +   1/x^2   =   1/2 where all variables   a,   b,   c, …,   x   must be different, positive integers, and … Continue reading

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## Sum of Prime Num3ers using each of the digits 1 through 9

Prime numbers under 1000 : 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, … Continue reading

## a + b + … + n = a * n

Sum of consecutive integers is equal to to the product of the first and the last terms: a, b, c, …, n   are consecutive integers. a + b + … + n = a * n For example, 3 … Continue reading

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## Table of numbers with 5 rows and 5 columns

Below is a table of numbers with 5 rows and 5 columns. From the table, choose 5 numbers in such a way that no two numbers come from the same row and no two numbers come from the same column. … Continue reading