Is it Prime (Or is it Memorex)?

A prime number is a natural number greater than 1, that has no positive divisors (factors) other than 1 and itself.

If you think of this definition in pictures of rectangles...

2 - ᥆᥆
3- ᥆᥆᥆
4 - ᥆᥆᥆᥆ or  ᥆᥆
                       ᥆᥆
5 - ᥆᥆᥆᥆᥆
6 - ᥆᥆᥆᥆᥆᥆  or ᥆᥆᥆
                             ᥆᥆᥆

Any number that can ONLY be represented by a straight line is prime.

Straight line is prime.

Integer Football Game

I came across this cool way to explain integers. Integer football. See for yourself at...

Integer Football

Fractions for Math Teachers

Pass The GED - Tips and Tricks

Many times it is the little things that stand between passing and failing. 

Here's a video to help everyone pass the GED exam by dealing with those little things.

Find the video here.

Khan Academy 200 Videos

The Florida Literacy Coalition 

has put together a playlist of   200

math instruction videos from the
Khan Academy. 



Here's the link...


Press here

Don't Call it Algebra (And Nobody Will Know!)

The word Algebra can be intimidating to GED students.

Many people have this conception of Algebra...

I always tell my students that they did algebra back in Grade 2 but they just didn't know it.

Grade 1 -    1 + 1 = ▭

We followed the directions and added the 2 numbers together and wrote "2" in the box.

1 + 1 = 2

Grade 2  Day 1

1 + 1 = ▭

We followed the directions and added the 2 numbers together and wrote "2" in the box.

Grade 2  Day 2

1 + ▭ = 4

We followed the directions and added the 2 numbers together and wrote "5" in the box.

1 + 5 = 4

It looked wrong, and we knew it was wrong, but we followed the directions that said we had to add the two numbers together and put the answer in the box.

After a leap in our thinking, we were able to say that...

1 + "something" = 4

That "something" is 3. 

1 + 3 = 4

1 + ▭ = 4        The ▭ = 3

So how about 1 + x = 4?

"x" is just a ▭                  x = 3

I tell my students that they did Algebra in Grade 2 so they can certainly do it now in GED study.

Hot Dog! It is the Top Dog! Speed Distance Time Triangles

Any question involving Speed Distance Time 

can be solved with this triangle...

and... your thumb

Oh, and a bit of multiplication and division...

But let`s worry about the 

first.

They key here is COVER. You COVER the letter of the element that you are looking for.

1) Here's a sample question...

You drive at a speed of 50 km per hour for 2.5 hours. What distance will you have driven? 

Let's get that thumb out!

You COVER the letter of the element that you are looking for. (Distance) The S and T are next to each other, so you need to multiply the values.

You drive at a speed of 50 km per hour for 2.5 hours. What distance will you have driven? 

50 X 2.5 = 125  What distance will you have driven? 125 km.

2) Here's another sample question...

You drive a distance of 125 miles at a speed of 50 km per hour. How much time will it take you? 

Let's get that thumb out!

You COVER the letter of the element that you are looking for. (Time)  The D is on top of the S, so you need to divide.  

You drive a distance of 125 miles at a speed of 50 km per hour. How much time will it take you? 

125 divided by 50 = 2.5   2.5 hours.

3)  Here's a third sample question...

You drive a distance of 125 miles in 2.5 hours. What was your average speed? 

Let's get that thumb out!

You COVER the letter of the element that you are looking for. (Speed) 

The D is on top of the T, so you need to divide.  

You drive a distance of 125 miles in 2.5 hours. What was your average speed? 

125 divided by 2.5 = 50    50 mph.

So how do you remember which letter goes where on this triangle? Which, by the way, is worth its weight in gold....

Easy... just thing of the Top Dog...

and guess what? The order of the S and T doesn't really matter. You'll get the same answer if the S and T are reversed. The important thing is to keep that DOG on top. 

Work SMART and not HARD

Purr Cent

What Does "Percent" Mean? 

I always say it means "for every hundred."   

Per = for 

cent (dollar, century) = 100.

Percent – think of Purr – Cent.    

One Hundred Cats. 

1 cat = 1 PurrCent.

1  / 

1/100 is...                1 %

9/100      is          9 %

18/100  is 18 %

        

I have to shut our 100 cats in the basement at night because they makes too much noise. 

Remembering that we put ALWAYS put cats in the basement...

So here's a question...

What is 18% of 25?

 18   X 25   

100 (basement)

18 x 25 = 450

Now divide 450 by those 100 pesky cats down in that basement!

450 divided by 100 = 4.5

 Answer - 18% of 25 is 4.5

Work SMART, not HARD

! #@$%&#@#

Ever wonder what that...

or...

                                                                                                                                                                                  

           

               

                                                           X

...key is for on your calculator? Well...

That's your gold plated 

short cut to solving those "arrangement"-type questions. 

You know (and love) the ones - "You have one red, one green, one blue and one yellow circle. How many ways can you arrange these 4 circles?"

So you might set out to make a grid or chart, starting with red. 

1) ০০০০

2) ০০০০

3) ০০০০

etc., etc., until your crayons and patience are worn out.

Or you could just enter 4 on your calculator and then press the factorial (x!) key (you might have to press shift first, depending on your calculator.) Bang. Done. Work smart, not hard.

Math Doctor Video - New Version

See Math Doctor Link for the new Math Doctor Video - write out a 10 by 10 multiplication in under 1.5 minutes.

Mean Median Mode Range - from www.showme.com

Do you know "Y" you were intercepted Part Three

"Do you know "Y" you were intercepted?" Part Three

 Which line has the equation          y = x + 6

Ok, smarty pants. What if 2 lines cross at the same spot and both have positive slopes? What then? (In this case, lines 5 and 8)

 

 

 

Then, we have to work out the slope of lines 5 and 8.

 

 

Think of jogging. If you want to go for a run up a slope in the morning, you must rise first before you run.

So...    to calculate the slope of a line...
use the formula...             slope = rise
                                                        run

Rise divided by run.

 

Rise is the vertical distance between two points on a slope. Run is the horizontal distance between two points on a slope.

 

Pick any 2 spots on line #5. Try to pick spots at the corners of the underlying grid.

 

slope = rise   2   = 1    run    2

 

Pick any 2 spots on line #8. Try to pick spots at the corners of the underlying grid.

 

 

slope = rise   4   = 2    run    2

 

Which line has the equation          y = x + 6

 

(Remember that this question can be written as y = 1x + 6. By convention, in algebra, the "1" in front of a letter or variable can be dropped for convenience.)

 

The slope of the line is associated with the value in front of the "x" in the given equation. The free floating number (in this case the "6"), is the place on the Y axis where the line crosses or intercepts.

 

Has to be line 5 for your answer, as it has a slope of 1. You are done.

 

Work SMART not HARD.

 

 

 

Do you know "Y" you were "intercepted"?

Look familiar? - Which line has the equation

 

 y = x + 6

These questions look harder than they are.

 

First of all, image you have been driving along and are suddenly "intercepted" by the police.

"Do you know "y" you were intercepted?" is probably the question you will be asked.

 

The key to this question is the "y" intercept, or the location at which the line crosses (intercepts) the "y" or vertical axis. (For some reason, nobody really cares about the poor old "x" axis. As with all "ex's", they are best left forgotten.)

 

y = x + 6 

 

The free floating number here is the 6. The only line that crosses/intercepts the "y"axis at 6 is line 5. Job done. You are finished.

 

Work SMART, not HARD!



10% Rule Part Deux - Using 1%

The 10% Rule RULES! Part Two

A quick review...

 

You can calculate any percentage using the 10% rule.

 

 

 

Example 1: What is 15% of 40?

 

 

Start by finding 10%.

 

To find 10%, think of 40 as 40.0

 

Move your decimal ONE place to the left and you have...

 

 

 

4.0  or 4

 

 

5% is half of 10%. Half of 4 is 2, so you need another

 

2

 

4 + 2 = 6

 

 

 

 

DONE! Work SMART not HARD

 

 

 

 

The 1% rule is just an extension of the 10% rule. 

 

 

Example 2: What is 16% of 40?

 

 

16% is just 10% plus 5 % plus 1%

 

 

 

Start by finding 10%.

 

To find 10%, think of 40 as 40.0

 

Move your decimal ONE place to the left and you have...

 

 

4.0  or 4

 

 

5% is half of 10%. Half of 4 is 2, so you need another

 

2

 

4 + 2 = 6

 

Now you just need that last 1%.

 

To find 1%, think of 40 as 40.0

 

Move your decimal TWO places to the left and you have...

 

 

.4

 

4 + 2 + .4 = 6.4

 

 

DONE! Work SMART not HARD

The 10% Rule RULES! Part One

 

You can calculate any percentage using the 10% rule.

 

No need to remember any rules, formulae or part/whole/percent triangles.

 

Example 1: What is 15% of 40?

 

 

Start by finding 10%.

 

To find 10%,

chop off the "0" in 40 and you have...

 

4

 

 

5% is half of 10%. Half of 4 is 2, so you need another

 

2

 

4 + 2 = 6

 

 

DONE! Work SMART not HARD

 

 

Example 2: What is 15% of 42?

 

 

There's no zero to chop!

 

Think of 42 as "42 decimal" or "42." Move that decimal one place to the left and you have 4.2

 

This is your 10%.

 

5% is half of 10%. Half of 4.2 is 2.1, so you need another

 

2.1

 

4.2 + 2.1 = 6.3

 

DONE! Work SMART not HARD

 

 

 

 

 

 

Quick Calculations - Use Half and Double

 

 

                                           X        


Work smart, not hard!

Double the...

... to...

 and halve the ...
 
 
 

... to...

 

 

100 X 8 = 800. Done!