September 18, 2014

The farmer and his three sons

Here's an interesting story problem that I received in an email!

A farmer died leaving his 17 horses to his three sons. When his sons opened up the will it read: 

Photo by
My eldest son should get 1/2 (half) of total horses;

My middle son should be given 1/3rd (one-third) of the total horses;

My youngest son should be given 1/9th (one-ninth) of the total horses.

As it's impossible to divide 17 into half or 17 by 3 or 17 by 9, the three sons started to fight with each other. So, they decided to go to a farmer friend who they considered quite smart, to see if he could work it out for them.    

The farmer friend read the will patiently, after giving due thought, he brought one of his own horses over and added it to the 17. That increased the total to 18 horses.    

Now, he divided the horses according to their fathers will.
  • Half of 18 =   9. So he gave the eldest son 9 horses.
  • 1/3rd of 18 = 6. So he gave the middle son 6 horses.
  • 1/9th of 18 =  2. So he gave the youngest son 2 horses.
Now add up how many horses they have:

    Eldest son  9
    Middle son  6
    Youngest son  2

    TOTAL IS 17

Now this leaves one horse over, so the farmer friend takes his horse back to his farm.

Problem Solved!

The moral:
The attitude of negotiation and problem solving is to find the 18th horse i.e. the common ground. Once a person is able to find the 18th horse the issue is resolved. It is difficult at times. However, to reach a solution, the first step is to believe that there is a solution. If we think that there is no solution, we won't be able to reach any!

Clever, isn't it!

September 15, 2014

Evaluation of a math assessment test - example

You might already know that the placement tests on my site work equally well as generic math assessment tests.

I also evaluate the test results for free.

Now you can see an example of one student's test results and my evaluation here.

Many students need to take two or even more tests in order to get a full picture of the gaps they have in their skills and knowledge. That was the case with this student also: she actually took three tests, grade 6, 5, and 4. I posted two of the tests and my evaluation at site. I hope it's helpful!

September 04, 2014

Number talks

Number talks are short discussions among a teacher and students about how to solve a particular mental math problem. The focus is not on the correct answer, but on all the possible methods of finding the answer.

Each student has a chance to explain their method, and everyone else will learn from other people's methods!

To start a number talk, the teacher gives the students a SHORT math problem to solve — but the students are not allowed to use a calculator or paper & pencil. The idea is to solve it in one's head!

For example, you could ask students to solve 5 × 18 using mental math.

Read more here - and see a great video by Jo Boaler. This is a "tool" you can't afford to miss as a math teacher!

August 29, 2014

Math Mammoth Grade 7-A is here!

I know it's Labor Day weekend, but...

Math Mammoth Grade 7-A is here!

cover for Math Mammoth Grade 7-A Complete Worktext Please note: Only part 7-A is available for now (as of August 2014). Part B is expected to be ready sometime in early 2015.

Math Mammoth Grade 7-A is the first half of the pre-algebra curriculum from Math Mammoth. Part A worktext deals with:
  • introduction to basic algebra concepts
  • integers and their operations
  • solving one-step equations, including with negative numbers
  • operations with negative rational numbers
  • solving linear equations and writing equations for word problems
  • graphing linear equations and an introduction to the concept of slope

=> Order grade 7-A here (at Kagi)

Also, grade 7-A is not yet available on any of the bundle products, CDs (such as the Light Blue series CD or All Inclusive CD) nor as printed copies. You can expect it to be included in the downloadabe bundles (Light Blue series, All Inclusive, Everything Bundle) by the beginning of September and on CDs after the first week of September.

I just know there are folks "chomping at the bit" to get it so I'm sending this notice now — as early as possible — when only the download of 7-A is available.

August 21, 2014

Story of Maryam Mirzakhani

I think some of you will enjoy reading the story of Maryam Mirzakhani, an iranian Mathematician, and a woman, who just recently won the most prestigious award in the world of mathematics: the Fields Medal.

She is the first woman to win a Fields Medal!

August 17, 2014

Math Mammoth August sale!

Math Mammoth and Make It Real Learning books

Sale at Kagi!

Get ALL downloads and CDs at Kagi store at 25%, 30% or even 35% off!

Use coupon code MAMMOTH25 at Kagi store.

  • Get 25% off when your order total is less than $50.
  • Get 30% off when your order total is at least $50 but less than $80.
  • Get 35% off when your order total is at least $80!

The sale lasts till September 2, 2014.

You will find links to order pages at Kagi all around site — they are located under each book's cover image. Or use these direct links to the order pages at Kagi:

August 07, 2014

SALE on Math Mammoth printed books!

Rainbow Resource is running a 20% off sale on the printed versions of Math Mammoth books! This offer runs till August 25, 2014.

August 06, 2014

Fun & artistic fractions tool

Here's an online fractions activity that is somewhat artistic and that some of you might find fun.

Unitize fractions on a grid

Conceptua Fractions is offering this tool for free during this summer. Here's a screenshot:

Unitize fractions tool

First, you drag a red rectangle or a triangle that is going to be your UNIT. It corresponds to 1.

Then, you make rectangles and triangles of the other colors. Your task is then to figure out their area compared to the UNIT you established in the beginning, and type it in as a fraction or a mixed number.

For example, in the picture below, my UNIT is actually 4 squares. The blue rectangle is 6 squares, so its area, compare to the unit, is 6/4 = 3/2.


August 04, 2014

Math Mammoth sales - August 2014


Math Mammoth is on sale at the co-op!

Check out

The discount level depends on the number of participants, and can reach up to 50% off!

This group buy is for the large bundle products & only for home schooling parents.

ALSO... I will run a sale for ALL the Math Mammoth and Make It Real Learning downloadable products & CDs at Kagi store, starting August 17th. 

And that sale is for everyone!

July 21, 2014

Worksheets for inequalities

More new worksheet generators... This one is for linear inequalities in one variable.

The worksheets are customizable in many different ways. You can ask the student to plot simple inequalities, such as x < -6 or write an inequality from a graph. One problem type asks you to solve the given simple inequality in the given set, such as solve x + 1 > -2 in the set {-9, 3,5,8, -2, 10}.

Then you can choose from six different types of linear inequalities to solve (such as one-step inequalities, two-step inequalities, or inequalities with variable on both sides).

You can also restrict the inequalities to the ones where you don't need to multiply/divide by a negative number (which would reverse the sign of the inequality).

These worksheets are meant for pre-algebra and algebra 1 (or grades 7-9).