2007 Mathematics Game

Posted on by Denise Gaskins

Are your students ready for a challenge?
The Math Forum: 2007 Mathematics Game will be a tricky one:

Use the digits in the year 2007 and the operations +, -, x, ÷, sqrt (square root), ^ (raise to a power), and ! (factorial), along with grouping symbols, to write expressions for the counting numbers 1 through 100.

  • All four digits must be used in the expression.
  • Only the digits 2, 0, 0, 7 may be used.
  • Multi-digit numbers such as 20, 207, or .02 MAY be used this year.
  • The square function may NOT be used.
  • The integer function may NOT be used.

Continue reading 2007 Mathematics Game

Negative Numbers for Young Students

Posted on by Denise Gaskins

[Rescued from my old blog.]

Would you like to introduce your students to negative numbers before they study them in pre-algebra? With a whimsical number line, negative numbers are easy for children to understand.

Get a sheet of poster board, and paint a tree with roots — or a boat on the ocean, with water and fish below and bright sky above. Use big brushes and thick poster paint, so you are not tempted to put in too much detail. A thick, permanent marker works well to draw in your number line, with zero at ground (or sea) level and the negative numbers down below.

Continue reading Negative Numbers for Young Students

Order of Operations

Posted on by Denise Gaskins

[Rescued from my old blog.]

Marjorie in AZ asked a terrific question on the (now defunct) AHFH Math forum:

“…I have always been taught that the order of operations (Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction) means that you work a problem in that order. All parenthesis first, then all exponents, then all multiplication from left to right, then all division from left to right, etc. …”

Many people are confused with order of operations, and it is often poorly taught. I’m afraid that Marjorie has fallen victim to a poor teacher — or at least, to a teacher who didn’t fully understand math. Rather than thinking of a strict “PEMDAS” progression, think of a series of stair steps, with the inverse operations being on the same level.

Continue reading Order of Operations

Our Tax Dollars at Work

Posted on by Denise Gaskins

Well, the new year has come, and it’s time to start gathering up receipts and thinking about tax forms.

Would you like to know that our tax dollars are doing good in the world? The National Science Foundation has spent many millions developing and promoting “reform” math textbooks, with encouragement from the U.S. Department of Education. Surely our public schools will now rise out of the doldrums and surge ahead in mathematical achievement, right?

Try for yourself this problem from one of the more famous/infamous of the reform math textbooks:

Can you find the slope and y-intercept of this equation?

10 = x – 2.5

And then check out this editorial[editorial has disappeared] at edspresso.com. You’ll be amazed at the answer!

Update: Checking on back-links, I discovered that this page had gone AWOL, so I’ll give you the “answer” from the teacher’s manual. The “slope” is 1 and the “y-intercept” is -2.5, according to Connected Math. Unfortunately, this equation actually describes a vertical line (undefined slope) at x=12.5 (never touches the y-axis).

Doesn’t bode well for “CMP helps students and teachers develop understanding of important mathematical concepts…”

Why Study Mathematics?

Posted on by Denise Gaskins
by d3 Dan via flickr

[Rescued from my old blog.]

What teacher hasn’t heard a student complain, “When am I ever going to have to use this?” Didn’t most of us ask it ourselves, once upon a time? And unless we choose a math-intensive career like engineering, the truth is that after we leave school, most of us will never again use most of the math we learned. But if math beyond arithmetic isn’t all that useful, then what’s the point?

If you or your student is singing the Higher Math Blues, here are some quotations that may cheer you up — or at least give you the strength of vision to keep on slogging.

We study mathematics…

Continue reading Why Study Mathematics?

Fraction Division — A Poem

Posted on by Denise Gaskins

[Rescued from my old blog.]

Division of fractions is surely one of the most difficult topic in elementary arithmetic. Very few students (or teachers) actually understand how and why it works. Most of us get by with memorized rules, such as:

Ours is not to reason why;
just invert and multiply!

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The Game That Is Worth 1,000 Worksheets

Posted on by Denise Gaskins

Have you and your children been struggling to learn the math facts? The game of Math Card War is worth more than a thousand math drill worksheets, letting you build your children’s calculating speed in a no-stress, no-test way.

Math concepts: greater-than/less-than, addition, subtraction, multiplication, division, fractions, negative numbers, absolute value, and multi-step problem solving.

Continue reading The Game That Is Worth 1,000 Worksheets

The “Aha!” Factor

Posted on by Denise Gaskins

[Rescued from my old blog.]

For young children, mathematical concepts are part of life’s daily adventure. A toddler’s mind grapples with understanding the threeness of three blocks or three fingers or one raisin plus two more raisins make three.

Most children enter school with a natural feel for mathematical ideas. They can count out forks and knives for the table, matching sets of silverware with the resident set of people. They know how to split up the last bit of birthday cake and make sure they get their fair share, even if they have to cut halves or thirds. They enjoy drawing circles and triangles, and they delight in scooping up volumes in the sandbox or bathtub.

Continue reading The “Aha!” Factor

Story Problem Challenge

Posted on by Denise Gaskins

[Rescued from my old blog.]

Well, my computer is still being rebellious, so I’m at dh’s office again to check e-mail while the kids are gone to karate. But I thought it was high time I got another entry up on the blog…

One of my favorite activities for Math Club is to have my students write their own story problems. Then we pass the problems around so everyone can try to solve them. With all the discussion of problem solving on the math forum lately, I thought it would be fun to extend the challenge to you all. Can you come up with a word problem for us to practice our problem-solving skills on?

Continue reading Story Problem Challenge

Finding the Limit

Posted on by Denise Gaskins

[Rescued from my old blog.]

Eldest dd had her first calculus lesson last night: derivatives. The teacher found the speed of a car at a given point by using the distance function, calculating the average speed over shorter and shorter time intervals. Dd summarized the lesson for me:

“If you want to divide by zero, you have to sneak up on it from behind.”

Of course, she understands you can’t really divide by zero, but I thought her tongue-in-cheek comment was a pretty good description of the process of finding the limit as delta-t approached zero.