Drexel dragonThe Math ForumDonate to the Math Forum

Ask Dr. Math

Middle School Archive

_____________________________________________
Dr. Math Home || Elementary || Middle School || High School || College || Dr. Math FAQ
_____________________________________________

TOPICS
space
This page:
  algebra checkmark

  Search
  Dr. Math

See also the
Dr. Math FAQ:
  order of operations

Internet Library:
  basic algebra

T2T FAQ:
  algebra help



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 Algebra
Stars indicate particularly interesting answers or good places to begin browsing.

Selected answers to common questions:
    Direct and indirect variation.
    Inequalities and negative numbers.
    Positive/negative integer rules.
    Solving simple linear equations.



Thinking about the Mediant of Two Fractions [12/10/2009]
One of my students noticed that when given 1/a and 1/b, the fraction 2/(a+b) always seems to be in between 1/a and 1/b. Is this a new fraction rule, or has this been discovered and proved before?

Thirds of Seven [07/24/1997]
Seven is equal to how many thirds of seven?

Thoughtful Trial and Error [05/21/2002]
Arrange the numbers 1 through 10 in a triangle so that all the rows of three numbers have the same sum, and all the rows of four numbers have the same sum.

A Three-Legged Stool [06/26/2001]
Why is a three-legged stool steady, while a four-legged stool can be wobbly?

Three Less Than a Number [08/19/2001]
What is "three less than a number"? I believe it is x-3 but I am being challenged that it is 3-x.

Three Pieces of Wire [01/07/1998]
A florist cuts a wire into 3 pieces. The 1st piece is 20% of the 2nd; the 3rd piece is 110% of the 2nd. The wire is 23 cm long; how long is each piece?

Three Weights [12/07/1997]
A boy selling fruits has only three weights, but with them he can weigh any whole number of pounds from 1 pound to 13 pounds inclusive. What three weights does he have?

Times Greater Than, Times As Much As [05/02/1999]
A number is five times greater than x. Will this number be 6x or 5x?

Top 10 Algebra Mistakes [05/23/1998]
What do you think are the top 10 mistakes that are made in algebra?

Total Test Questions [09/21/1997]
On her biology test, Cathy answered 5/6 of the questions correctly...

Train and Tunnel [7/18/1996]
A train passes completely through a tunnel in 5 minutes. A second train, twice as long, passes through the tunnel in 6 minutes...

Train B Overtakes Train A [01/17/2002]
Train A leaves the station traveling at 30 miles per hour. Two hours later train B leaves the same station travelling in the same direction at 40 miles per hour. How long does it take for train B to catch up to train A?

A Train Breaks Down [06/30/2001]
A train breaks down an hour after starting its journey. After repairs, it can only continue at half its original speed and arrives at its destination two hours late...

Train Overtaking Another Train [10/19/1996]
Two trains leave a station, one an hour after the other...

Translating English to Algebra [06/27/2002]
Write an algebraic expression for 'Seven more than twice a number'.

Translating Word Sentences to Math Sentences [03/10/2004]
"Six more than three times x is four times two less than x" was translated in our textbook to 6 + 3x = 4(x - 2). Some of my students felt it should be 6 + 3x = x - (4*2). Is there a true rule or law of mathematics or some definite tradition as to the interpretation of sentences?

Traveling Trains and Nonlinear Systems [07/16/1998]
A train leaves town A and travels 540 miles at a uniform speed, followed an hour later by another train.... What were the speeds of the trains?

Triangle and Trapezium Ratio [10/26/1998]
ABCD is a square with sides of length 4 cm. Find M on BC so that the ratio of triangle ABM and trapezium ADCM is equal to 1/3.

Turning an Equation Upside-Down [07/09/2001]
After this step: 2/h = (a+b)/ab, a book shows this: h/2 = (ab)/(a+b). Can you simply invert the fractions and maintain the equivalency?

Turning Word Problems into Equations [04/15/2002]
I don't like turning word problems into equations because it is too confusing. Is there a technique that might help me out?

Turning Word Problems to Equations [03/08/2001]
How do you turn English sentences into math equations?

Two Cars on Crete [08/15/1997]
Find the speed of the car from Phaistos.

Two Numbers with Equal Sum, Product, and Quotient? [05/07/2007]
Find two numbers such that when you find the sum, product, and quotient of the two numbers they are all equal.

Two Step Equations [02/24/1998]
How to solve two-step equations.

Two Steps Forward, One Step Back [10/14/2003]
A salmon swims 30 feet upstream in 5 seconds, then rests for 2 seconds. If she moves 10 feet downstream during each rest, how long does it take her to swim 1010 feet?

Two Trains with a Twist [9/11/1996]
The local train heading for Westford at 60km/h and the express train heading for Eastford at 80 km/h pass each other at Centerville while heading in opposite directions...

Two Ways to Solve an Equation [1/23/1996]
x + 3 = 7

Understanding Rectangle Area and Perimeter [11/08/2002]
True or false: if the perimeter of a rectangle increases, the rectangle's area always also increases.

Unique Values for x, y [9/10/1996]
Find unique values for x and y so that x+y and y*x equal the same number.

Use Factoring to Find Two Consecutive Integers... [7/31/1996]
Find two consecutive integers whose product is 56.

Using Euclid's Algorithm with Three Numbers [11/05/2003]
How do I find the GCD of three integers using Euclid's Algorithm? I am not sure where you plug the third integer into the algorithm.

Using Guess and Check to Start an Algebra Problem [02/15/2008]
Laura is three times as old as Maria was when Laura was as old as Maria is now. In two years Laura will be twice as old as Maria was two years ago. Find their present ages. Dr. Ian shows that by first making a guess and checking it you can then easily write the algebraic equations needed to solve the problem.

Using Interval Notation to Express Answers [12/03/1996]
Solve for x in the inequality x/(x+3) >= 1/(x-1) and express the answer in interval notation.

Using Variables to Solve Word Problems [05/10/1998]
Susan puts only dimes and quarters in her coin bank ...

Variable Expressions with Parentheses [9/9/1996]
How do you solve 2(x-1)-3(2-3x)-(x+1) using the distributive property?

A Variable for Each Digit [11/28/2001]
A husband's age is the inverse of and greater than his wife's age... Some examples are 82,28 or 54,45. Is there a way to solve this without simple trial and error?

Velocity and Time [02/11/1999]
A car averages 30 km/hr the first half of a trip, and 50 km/hr the second half of the trip. What is the car's average velocity for the trip?

A Velocity-Time Problem [02/16/1999]
If you drive 40 mph instead of 30 mph, you save 30 seconds per mile, but if you make the same 10 mph increase from 70 mph to 80 mph, you only save 5.6 seconds per mile. Why?

Venn Diagram - Fast Food Restaurants [05/09/2002]
From a list of how many restaurants serve what kinds of food, deduce the total number of restaurants.

Verifying the Solution to an Inequality ... by Substituting? by Checking Boundaries? [04/28/2010]
A student is confused about how to verify work on a linear inequality in one variable, which also features fractions and sign changes. Doctor Peterson responds with an explanation of how to check a solution to an inequality: by testing its boundaries.

Page: [<prev]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 [next>]

Search the Dr. Math Library:

Search: entire archive just Middle School Algebra

Find items containing (put spaces between keywords):
 
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words


[Privacy Policy] [Terms of Use]

_____________________________________
Home || The Math Library || Quick Reference || Search || Help 
_____________________________________

© 1994-2014 Drexel University. All rights reserved.
http://mathforum.org/
The Math Forum is a research and educational enterprise of the Drexel University School of Education.The Math Forum is a research and educational enterprise of the Drexel University School of Education.