Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [arithmetic]

Questions on basic arithmetic involving numerical quantities only. Questions involving variable values (other than the result of the operation) should be placed under the (algebra-precalculus) tag. Questions about number theory (sometimes called "arithmetic") should not use this tag and should instead use (number-theory) or (elementary-number-theory).

Arithmetic is defined as operations upon numbers using $4$ main operations along with many others:

addition - the sum of two numbers

subtraction - the difference of two numbers also defined as the addition of negative numbers

multiplication - the area of a rectangle with sides of lengths equal to the two operands

division - the number of times one number can be subtracted from another before equaling zero. Sometimes it will allow decimals and in other cases there will be a remainder left over when a number doesn't go into another evenly

See Arithmetic.

6283 questions
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What is the difference between a quadratic equation and a quadratic function?

I cannot dicepher the difference between a quadratic equation and a quadratic function. I read the following "A quadratic equation can tell us a lot about the graph of a quadratic function." I see the following equation: f(x) = 10x^2 - 8x That to…
JohnMerlino
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quick basic math equation question

I've got a solution to a economy class calculation, but I can't figure out how they came to the answer. Could you help me? -5p + 80 = 8p +-50 .......? = ......? 120 = 12p p = 10 Extra: do you know which rule they are using to get from the first…
Frank
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basic proportions, why the results are inconsistent?

Simple 3rd grade problem: A friend got a 10% raise to its salary. He got angry and asked for more. After much Negotiation he got another 10% raise on top of the first one. He asked me to check how better is he fairing with the 2 salary raises. I…
Draconar
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Solving a non-linear congruence

How would I go about solving the following: $$x^2+1\equiv2\pmod8$$ I know I can subtract, and I get: $$x^2\equiv1\pmod8$$ I'm not sure if I am allowed to square root both sides, or if I should employ a different technique?
Ian Murphy
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Get values of multiple variables from simple additions

What is the process to get the values of each variable when I only have these calculations to go on? These are the sums: a + b = 270 c + d = 190 a + d = 230 b + c = 230 e + a = 180 e + d = 150 I'm not even sure if this is solvable, or if there are…
Diederik
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Modular Arithmetic Involving Remainders

Using modular arithmetic, solve the following: Find the remainder of $(2014^{2015} \cdot 2016^{2017}) + 2018^{2019}$ when it is divided by 13. I have no idea where to start. I've tried putting this in (mod 13) but I'm not sure where to start or even…
Ian Murphy
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Mowing the lawn alone vs. together

The question is: Nils mows the lawn in 3 hrs alone. Nils and Jonas mow the lawn together in 2 hrs. How quickly would Jonas mow the lawn alone? My thinking: If Nils mows the lawn alone in 3 hrs, he mows 1/3 the lawn in 1 hr. If Nils and Jonas mow the…
Gordon
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how to calculate gross salary when net salary and percentage of deduction is known

When net salary is 10350 and 13.75% pf deducted how gross amount is calculated.. For eg: If gross salary is 12000, pf is 13.75% then net salary= 12000* 13.75% = 10350 But how to calculate reverse way wen we know net salary as 10350…
rh160
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How to round "correctly" (to certain level of accuracy)

Say I have the number 0.73992 and I'm rounding to 3 decimal places. My instinct would be to write 0.740 (3dp). But surely that implies that it is exactly 0.740. The only other alternatives are to write 0.7399 (4dp) or 0.74, neither of which are to…
hnefatl
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Division of number of days to get a year

Assuming a year has $360$ days and $12$ months of $30$ days each. I can say that adding $5$ days $2$ months and $15$ years to $17/10/2014 (dd/mm/yyyy)$, is $22$ days $12$ months and $2029$ years Now…
εν οίδα ότι ουδέν οίδα
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Solving a arithmetic sequence problem

Irene deposited \$200 in a bank on 1st January and on the first day of each of the following months. At the end of June, when the interest was calculated, he found that his account balance was \$1206.30. Find the rate of a simple interest paid by…
user184563
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Arithmetic Sequences Problems

Find the sum $S$ defined by $$S = \sum_{n=1}^{20} \left(3n-\frac{ 1}{2}\right).$$ I have $$S = 3 \sum_{n=1}^{20} n- \sum_{n=1}^{20}\frac{ 1}{2} = 3(210) - 10 = 620,$$ but the answer is supposed to be 1380?
user184563
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Arithmetic: simple interest question

Alice puts 3400 dollar on her bank account with interest rate 3,7%. How much interest does she receive in the second year? I answered: $3525.8\cdot1.037-3400\cdot1,037=130.5$, but this is the incorrect answer. Can someone help me?
rae306
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How to solve this age probem - ration using singapore mathematics?

I am new to Singapore mathematics. I could solve this question very easily using algebra. However, I feel that you get a good picture - conceptually when you try to solve questions using singapore mathematics. The variables x,y - algebra hide the…
dexterous
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Running 3 miles in 20 minutes, how many miles can one run in 50 minutes?

Maria can run 3 miles in 20 minutes. At this rate, how many miles could she run in 50 minutes? I have tried dividing 3 by 20 to get the unit rate.
Lupe
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