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 TOPICS This page:   division    Search   Dr. Math See also the Dr. Math FAQ:   divisibility rules and   order of operations Internet Library:   division MIDDLE SCHOOL About Math Algebra    equations    factoring expressions    graphing equations Arithmetic    division    exponents    factorials    factoring numbers    fractions/percents    logarithms Definitions Geometry    2-dimensional      conic sections/        circles      triangles/polygons    3D and higher      polyhedra History/Biography Logic Measurement    calendars/      dates/time    temperature    terms/units Number Sense    factoring numbers    negative numbers    pi    prime numbers    square roots Probability Puzzles Ratio/Proportion Statistics Word Problems Browse Middle School Division Stars indicate particularly interesting answers or good places to begin browsing. Selected answers to common questions:     Dividing fractions.     Long division.     Number sentences.     Order of operations. 2a/5 or 2a Divided by 5? [12/13/2001] Why, when writing a division problem, do you write 2a over 5 instead of 2a divided by 5? (9/2)/(3/4): A Picture [03/27/2003] We were trying to find a division fraction question and everything we came up with turned into a multiplication fraction problem. Why is that? Basic Real Number Properties [07/31/1997] I need information about basic real number properties: associative, commutative, closure, identity, inverse, distributive. Decimal in the Denominator Visualized [12/13/2013] A young adult struggles to visually model and evaluate a fraction that has a decimal in its denominator. Doctors Jerry and Peterson suggest equivalent fractions, inverses, and scale models. Division [11/25/1997] How do you divide 1,000,000,000,000 by 999,999,999,999,999,999,999? Division by Zero [11/2/1994] Why can't you divide a number by 0? Division Direction [03/30/2015] An adult wonders why the standard algorithm for division does not follow the right-to-left order of the algorithms for the other basic operations. With copious examples, Doctor Peterson reveals that efficiency explains why manual division proceeds faster when performed left to right. Explaining Fractions [11/06/2001] I am a practicum student in a 8th grade math class. The teacher and I don't know how to explain to the students why you can do this manuever. c=d/g; c/d=g; d/c=g. Least Common Multiple Puzzle [03/24/2003] What is the smallest number divisible by 1,2,3,4,5,6,8,9,10 that is not 3600? Least Common Multiple Word Problem [12/10/1996] Each of three businesses receives different sized cartons of glasses. If all three receive the same number of glasses and none of them receive more than a thousand glasses, how many glasses and cartons are in each shipment? Long Division [08/23/1998] My biggest problem is long division. For example, what is 73/4? Manipulating Positive and Negative Numbers [8/9/1996] Could you explain the rules for adding, subtracting, multiplying, and dividing positive and negative numbers? Multiples of 9 Number Puzzle [03/23/2003] If you take a two-digit number, add the digits, and subtract the sum from the original number, why is the answer always a multiple of 9? Order of Operations: Math vs. English; Calculators [11/13/1996] What is 144 divided by 3(8+4)? 4 or 576? Probability of Sky Falling is 0/0? [3/3/1995] When asked the probability that the "sky will fall" one student responded "0/0". What should we have told this 8th grade student about dividing by zero? Reciprocals [12/19/1996] What is the use of reciprocals? Restrictions on Variables in Division [8/4/1996] What are the restrictions on the variables in (y^3+8)/(y^2+3y+2)? Wording Division Problems [08/10/1998] How would you clarify the wording of division problems like "divide into" or "divide by"? Working with Integers [01/12/1999] Could you explain how to divide, multiply, add, and subtract integers? 1 Divided by Very Small Number [8/6/1996] 1/0.00000000000000000000000000000000001 = ? Adding and Subtracting Roman Numerals [10/26/1999] How can I add and subtract Roman Numerals without converting them to regular numbers? What did the Romans do to solve this kind of problem? Are Subtraction and Division Commutative and Associative Operations? [05/15/2008] I don't agree that subtraction and division are not commutative operations. If we define a - b as a + (-b), then it commutes correctly into (-b) + a. So why does everyone say subtraction is not commutative? Brackets [01/29/2001] Please explain how brackets [] work. Calculating Percentage Markup Versus Profit [01/23/2004] In order to figure a profit of 10% I would normally take my cost and then multiply by 1.1 to find the selling price. My employer tells me that in order to find a 10% profit I should divide my cost by 0.9, but I don't understand how this is 10%. Can you please explain? Cancelling Fractions [06/03/2003] I am reading a book on algebra. The author states that cancelling is division too and then shows the following without any explanation of how it's done... Cars in Rows, with Remainders [01/22/2013] A student struggles to figure out what positive integer smaller than 1000 groups into fives with remainder one, or into four with remainder one, or nine evenly. Doctor Ian introduces divisibility, methods — and several kinds of shortcuts. Casting Out Nines to Check Arithmetic [08/26/1999] Can you explain how to use the 'casting out 9's' technique in a way that a 6th grader can understand? Comments on Dividing Fractions [03/15/2007] A question on how to divide fractions leads into comments on how division and subtraction can be thought of as multiplication and addition of an "inverted" number. Commutative Property and Division [02/21/2002] I am trying to prove that the commutative property following certain rules will work in all circumstances for division... Compatible Number Estimating [01/31/2002] My homework is on compatible numbers to estimate quotients - for example, 1,625 divided by 38. Compatible Number Method for Estimating [09/10/2001] We are supposed to estimate using compatible numbers. How does one estimate something like 574/8? Confusion over Interpretation of PEMDAS [03/24/2005] Students take PEMDAS letter by letter, tending to do all multiplication before any division, rather than working from left to right. Here's a suggestion on how to help avoid that confusion. Converting Bits to Megabytes [02/12/2001] The human brain will store 100 trillion bits in its lifetime. How many million megabytes can your brain store? Counting Days of the Week [02/02/1999] If today is Thursday, what day would it be 120 days from now? Counting Techniques [12/29/1997] Find the number of positive divisors of 17640, inclusive of 1 and 17640 itself. Find the number of odd integers between 2000 and 7000 that do not have repeated digits. Cutting An Equal Number of Slices of Cake [07/13/1998] One cake is 35 slices and another is 42 slices. If the cakes need to have the same number of slices, how many slices should they have? Deciding How to Express the Answer to a Division Problem [07/22/2006] When dividing something like 7 by 2, is it best to express the answer as 3 1/2, 3.5, or 3 remainder 1? How do I decide which form to use? Definition of Quotient [11/13/2008] If I divide 15 by 2, I always thought that the quotient was 7 and the remainder was 1. But I've seen that the quotient can also be 15/2. How can quotient have different meanings? Definition of Vinculum [10/21/2004] Is the bar placed over the set of repeated digits in a repeating decimal called a vinculum? I've heard that but I can't confirm it. Determining If a Large Number is Divisible by 11 [10/22/2003] I just learned a trick to decide whether a large number is divisible by 11 or not. Why does the trick work? Page:  1  2  3 [next>]

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