# arithmetic's questions - English 1answer

73 arithmetic questions.

### 9 Products or sums

1 answers, 113 views no-computers arithmetic
Arrange the integers between 1 to 20 on twenty of the cells of this board, precisely two on each row and each column. The sum or product of the two numbers in each row must be the number on its right, ...

### 1 Sums or products

Place the numbers 1 to 12 on twelve of the cells of this board, precisely two on each row and each column. The sum or product of the two numbers in each row must be the number on its right, while the ...

### 4 Use 2, 0, 1 and 8 to make 71

Use all and only the digits $2,0,1,8$ once each to make the number $71$. Allowed operations; anything not on this list is banned: $+,-,\times,\div, ()$ (parentheses and/or choose function) ...

### 3 make a sum with cards

2 answers, 126 views arithmetic cards
Take the numbered diamond cards in a standard deck, that is those from 2 to 10. You may use some of them to form a sum: for example 23+45=68. What is the maximum result you may obtain? I hoped there ...

### 7 Aiming for the 24

1 answers, 956 views no-computers arithmetic
6 1 3 4 = ?? Using four basic math signs (+, -, *, /) and brackets, for instance: 6 * (1 + 3) - 4 = 20 6 * 1 * 3 + 4 = 22 6 + 13 + 4 = 23 (6 + 1)* 3 + 4 = 25 61 - 34 = 27 Try ...

### 4 A special square

1 answers, 151 views no-computers arithmetic
Is there a four-digit square number which has at least one digit in common with every other four-digit square?

### 7 My Sister's Six Children

My sister has six children whose ages add up to 40. The ages of any two of her three boys have a common divisor greater than 1, and so do the ages of any two of the ages of her three girls. However, ...

### 17 A partition of 1000 into nine parts

1 answers, 463 views number-theory graph-theory arithmetic
The sum of nine whole numbers is 1000. If those numbers are placed on the vertices of this graph, two of them will be joined by an edge if and only if they have a common divisor greater than 1 (i.e. ...

### 13 My Three Children

The sum of the ages of my three children is 40. Though the ages of my two daughters are relatively prime (i. e. they have no common divisor), the age of each of them does have a common divisor greater ...

### 21 A Tour Around a Triangle

1 answers, 697 views number-theory graph-theory arithmetic
Place the 18 even integers between 2 and 36 in the empty nodes of this triangular graph in such a way that if a path is drawn by coloring in red all the edges joining any two nodes whose numbers add ...

### 5 Six sisters on the ski lift

1 answers, 325 views number-theory arithmetic
The sum of the ages of six sisters known to me is 92. Though there is no single whole number greater than 1 that simultaneously divides the ages of any three of them, I did notice this morning, while ...

### 22 The 10,958 Problem

Here is the task: Write down 10958 using all 1-9 digits in ascending order and only one time. You are allowed to: 1) group digits into numbers 2) use 5 basic operations: + - * / ^ ("^" ...

### 10 Four Marathon Runners

3 answers, 1.189 views number-theory arithmetic
Four marathon runners, each identified with a positive whole number, sit around a table. Each of them notices that their own number has a common divisor with the number of the runner sitting on his ...

### 1 Make numbers 1-30 using 2, 0, 1, 9

This is very similar to the 2, 0, 1, 8 problem. Just try to make all numbers 1-30 using the digits 2, 0, 1, 9. Rules: Use all four digits exactly once Allowed operations: +, -, x, ÷, ! (factorial), ...

### -3 Calculate cost of excess water consumed [closed]

1 answers, 107 views calculation-puzzle arithmetic
100 Liters of water is available equally in a month for consumption among 5 members @ 1 dollar per liter. If some members don't use their own available 20 liters, it can be used by the others at the ...

### 15 A partition of 100 into nine parts

3 answers, 1.924 views mathematics graph-theory arithmetic
The sum of $9$ positive natural numbers, not necessarily distinct, is $100$. If placed appropriately on the vertices of the following graph, two of them will be joined by an edge if and only if they ...

### 5 The mathematical quiz

5 answers, 396 views mathematics arithmetic
There are 4 equations. What should I put in place of the ? in the last one?1 + 4 = 5 5 + 3 = 11 7 * 7 = 61 10 - 1 = ?

### 3 Curiosity of February 5$^{th}$

5 answers, 581 views mathematics arithmetic time
Some people write February 5$^{th}$ using the md format, as $2.5$ or alternatively as $2/5$. Note that $2.5 \times \frac25 = 1$. Is there any other date satisfying $a.b \times \frac{a}{b} = 1$? ...

### 8 My forgotten PIN

3 answers, 498 views number-theory arithmetic
I´ve forgotten my PIN, a four-digit number. All I remember is that it is a perfect square, and that it has at least one digit in common with every other four-digit square number. What is it?

### 13 My five daughters

5 answers, 4.258 views number-theory arithmetic
The sum of the ages of my five daughters is 43. The ages of any two of them have a common factor greater than 1. How old are my daughters?

### 8 A unique partition of 200 into 6 parts

2 answers, 736 views number-theory arithmetic
The sum of six positive integers is 200. If placed appropriately on the vertices of this graph, two of them will be joined by an edge if, and only if, they are not relatively prime, that is, if they ...

### 7 Videogame salesmen

Two gamers sell their collection of XBOX games. They've got as many Euros as there were games in the collection originally for each game. They split the money by having the first gamer take 10 Euros ...

### Continue sequence

2 answers, 188 views number-sequence arithmetic sequence
Son asked such a task. Continue the number sequence5, 7, 8, 12, 11....The son is in the second grade. They studied the operations of addition, subtraction and ...

### 6 How many multiplications to find n^k given n, for general k?

1 answers, 455 views mathematics optimization arithmetic
I was looking at the nice puzzle Find $n^{23}$ with the least multiplication. My first instinct for this would have been to find $n^{2^i}$ for each $i$ first and then multiply these together as ...

### -6 What's My Number (Math Riddle) [closed]

1 answers, 536 views mathematics arithmetic
I am thinking of a number. I multiplied by 3, subtracted by 8, doubled the result, and added 14. Then i added on 50% of what I had and subtracted 11. Then i divided by 5. After all that, I was left ...

### -4 Series Problem By Gpuzzles - I Have Doubt [duplicate]

1 answers, 303 views mathematics arithmetic
gpuzzles.com is one of my favorite sites along with StackExchange, but can someone please elaborate on the answer? Problem: Can you solve the number series problem by replacing boxes with numbers 1, ...

### 9 Sum self enumerated digits

Please fill in the entire summations for lines 4 through 9 and just the total for line 1,000,000.         1.     1   =   1   ...

### 14 Why you shouldn't buy cheap puzzle books

Backstory contains important information, but nothing hidden. Also, tl;dr parts are bolded, but I can't guarantee I didn't forget bolding some part. Recently there's been a grid-deduction craze here ...

### 3 Turn based Number game

1 answers, 162 views strategy game arithmetic game-theory
You and a friend take turns saying positive integers greater than one. You can't say a number that is a multiple of previous numbers or a sum of multiples of previous numbers. For example, if A says 3 ...

### 5 How old was Matthew when his brother died?

When Sam's father died, Sam's uncle, Matthew (his fathers only brother) was twice the age of Sam minus 14 years. As Sam and Matthew grew older they became friends. When the younger of the two turned ...

### 3 Complete the equality (medium-hard)

Complete the equality to make it true:1 1 1 1 1 = 945Using similar logic, solve for this:1 1 1 1 1 = 80Info: You should ...

### 4 Complete the equality

4 answers, 276 views mathematics arithmetic
Complete the equality to make it true:1 1 1 1 = 5You can add any math operation or symbol to the left side. You cannot change right side nor the ...

### 4 Remove two digit/symbol to find equality

1 answers, 134 views mathematics arithmetic
Find the equality by removing any two digits or symbols (of course, except equal sign) $4\div3+63=9-23\times7\div3$ For example, if the equation below was given, Example: $91-81=45+12\div3-85$ ...

### 15 Buttons on an old non-scientific calculator are less sensitive

All 5 numbers are entered in an ascending order. These numbers are in an arithmetic progression. The value of the fifth number, i.e. the largest number, is less than 99. While adding these ...

### 13 Yet another matchstick puzzle

14 answers, 3.167 views arithmetic matches
Inspired by this post, here there is my attempt at a matches' puzzle. The expression 1 = 850 - 9 - 6 is obviously wrong: move exactly three matches to obtain a correct expression. Rules are: This ...

### 6 Difficult sequence

Here I go : $3 + 5 + 6 = 15 \ 18 \ 72$ $5+ 5 + 6 = 25 \ 30 \ 94$ $5 + 6 + 7 = 30 \ 35 \ 85$ $5 + 5 + 3 = 25 \ 15 \ 73$ $9 + 4 + 7 = 36 \ 63 \ ?$ Replace ? with appropriate number

### 8 Little Red Solving Hood goes one-stop swapping

1 answers, 337 views arithmetic computer-science
Moral of the story:   Two stored values may be swapped arithmetically with 4 or fewer variable references. Puzzle of the story:   Can you exemplify the moral?   (With 10 or ...

### 1 Two Three-Digit Numbers Added to Make Four-Digit Sum. No Number Can Repeat Itself.

A friend posed this question to me a few days ago, and I just haven't been able to get it off of my mind. "There are ten numbers from 0 to 9. You can use any number you like in the box, but the ...

### 10 The Vacuumed Quotes

1 answers, 546 views cipher arithmetic
A colleague of mine likes to put his favorite quotes up on the fridge using those little magnetic letters. This morning the cleaner came and accidentally vacuumed up all the letters. We were able to ...

### 12 KenKen Zen: A journey begins

Let us shy away from the materialistic opulence of 361- cell KenKen layouts (−9 to +9, squared).  Let us contemplate a modest KenKen journey, unburdened by gratuitously ...

### 4 The Autonumerigram Challenge [duplicate]

Some phrases both refer to a number, n, and are comprised of n alphabetic characters. I call any such phrase an autonumerigram. For example, four has 4 letters seven plus seven has 14 letters ...

### 3 KenKen Zen: The Cluelessening

As our KenKen voyage of cluelessening­* began, some clues remained entirely hidden from us.  Though much remains to be discovered, we may now be entrusted with all clue amounts at once.&...

### 1 Fill 3x3 magic square with distinct numbers 1..60 summing up to 69

I have to fill a whole 3x3 grid in such a way that the sum of each row, column, and main diagonal is 69. I couldn't find any logic to fill it up. I have to use distinct numbers from 1 to 60 for this. ...

### 31 Sum other numbers

4 answers, 1.625 views lateral-thinking arithmetic
Begin with a flagrantly erroneous summation and a woefully vacant substitution table. 234 + 5 Digit 2 3 4 5 6 7 8 ------- ...

### 19 Honeydripping around the clock

What path could a honeybee follow, beginning and ending at top center, visiting every empty cell exactly once and dripping 2 drops of honey into the last cell? Start ...

### 9 H-one-one-oneycomb

What path could a honeybee follow to fill all cells with honey, beginning and ending at the center and visiting every cell exactly once? At first the only ...

### 10 How to fill a honeymoon

How can a honeybee visit all cells exactly once in this crescent shaped honeycomb, beginning at the bottom tip and ending at the top? The starting cell, at ...

### 3 Get the largest number using the crazy circuit board

There is a crazy circuit board with three kinds of elements which can change the signal value. All intersecting paths are connected (but paths touching by a single point are disconnected). There is ...

### 3 Arithmetic Puzzle

1 answers, 162 views puzzle-identification arithmetic
The British Independent and i newspapers run what they call an "Arithmetic Puzzle", which comprises a grid of nine cells, with each cell separated from the others by arithmetic symbols: (+ - / *), and ...

### 1 It is related to a type of mathematics game

2 answers, 251 views formation-of-numbers arithmetic
Start with two digits from $1\dots9$ to form a $2$-digit number. Multiply this number by a single digit from $1\dots9$. Add the result to another two digit number from $1\dots9$, and calculate the ...