We're Not Gonna Take It!

"We've got the right to choose it
There ain't no way we'll lose it." (Twisted Sister)



O.K. - I found these tips from- Basic mathematics.com

And it makes sense. Why take the question the way it is given to us?

Why not twist or rearrange things to our advantage?

Examples of additive compensation

Add 97 + 64

It may not be easy to add 97 and 64 mentally. However, one small adjustment

such as rewriting the problem as 97 + 3 + 61 can help us to get an answer quickly

97 + 3 + 61 = 100 + 61 = 161

Add 25, 27 , and 18

It is not easy to do any of these additions mentally.

25 + 27            25 + 18         27 + 18                             

However, if we take 2 from 27 and add that to 18, the problem becomes

25 + 25 + 20 and this is very easy to do mentally since 25 + 25 = 50 and 50 + 20 = 70

Examples of equal additions method

 The equal additions method is a compensation used when doing subtractions.

Subtract 39 from 57.

57 - 39 can be thought of as  58 - 40

58 - 40 = 18

To make the subtraction 58 - 40, we added 1 to 57 and 39 so that we still have the same subtraction problem.  

Work SMART, not HARD!

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.

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.

Dividing Fractions #%$^&*() Don't choke!!!!!!!!!!!!!!!!!

Dividing fractions? Don't choke!!!!!!!!!!!!!!!!!

Isn't one of the fractions supposed to be flipped around or something? I can never remember which one...

Here's the easy way to remember the process...

(Note - you are under no obligation to use this simple and easy to remember explanation. You can use any unnecessarily long and convoluted method you wish to help explain it.)

So what is 6/31  divided by 2/3?

Here's dad and son. Dad is 6 feet tall and aged 31. Dad is first in age so he's the first fraction.

Son is 2 feet tall and aged 3 months. Son is second.

Son starts to choke...

Dad, being dad, starts to swear. (He never swore much before the had children.) Swearing is bad (apparently), so we cross this out. Son gets turned upside down and becomes 3/2. Choking stopped!


So now we have 6/31  X   3/2

Solve as you would a normal fraction multiplication question. Remember....

Leave the first fraction alone. The guy is trying to save his son's life, here, people, so leave him alone to get on with the job. Please disperse. Back away from the man. Go about your business.

Turn the 2nd fraction upside down.

Put an X between your two fractions.

Solve as you would a normal fraction multiplication question.



Work smart, not hard.

Exponent Secrets

See this link           http://www.mathsisfun.com/activity/secret-safe-exponentially.html  for a great explanation of exponents.

Come Undun

From  de.wikihow.com

Mean Median Mode Range - from www.showme.com

Circumference

Formula for Circumference?

Well - if you eat a pie a day, you will get a big circumference. (Distance around your middle.)

 

C = ∏   x  D    (diameter)

Find the diameter (or double the radius if the radius is given), multiply by pi and you will get the circumference.












Work Smart, Not Hard!

Congruent! Gruesome! Grew Some!

Teacher: "Chris, use the word 'gruesome' in a sentence."
Chris: "A prisoner didn't shave for a week and grew some whiskers."

 

What's this got to do with congruency?

"Congruent" - definition: geometric figures of the same shape and the same size

Note: The figures don't have to be facing in the same direction to be congruent. Think of it as...

"If I cut one shape out, I can rotate it, place it over the top of another shape  and the two shapes will match up exactly."

What if our prisoner above (our con) had a twin brothers who also grew some whiskers....

 

 

Even though con #2 is facing in another direction, he and con #1 are, indeed, congruent.

On the Way to Grandma's House

Look familiar?

7 (x + 2) = 28

 

Solve for x

 

 

This is a Little Red Riding Hood question. Watch out for the...

Little Red Riding Hood decides to take 7 baskets... to Grandma's house. Each basket contains...

   an  X

and 2 apples (or whatever you'd like)

 

Therefore...



 

Little Red Riding Hood will carry a total of 7x and 14

 

 

Now we have a simple equation

 

7x + 14 = 28

 

 

We will employ the dump, shove and divide method to solve it.

 

 

1) DUMP 14 off each side of the equation so you have 7x = 14

 

 

2) SHOVE

the 7 under the 14

 

 

 

14

__

 

 7

 

 

 

 

3)

...14 by 7. Your answer is 2.

 

 

 

 

Done! 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

 

 

 

 

 

 

Neat Trick for Squares - Well Some of Them

If you are squaring a number that ends in 5, your answer will end in 25.

There's the early Christmas present...

That's the easy part. What about the hard part?

There isn't one...

2

15

 

You know your answer will end in 25...

 

Now, multiply the first digit (the 1 in 15) by ONE larger (2)

 

1 x 2 = 2

 

Stick the 2 in front of the 25 and you have your answer...

 

225

 

Try squaring 25...

 

You know your answer will end in 25...

 

Now, multiply the first digit (the 2 in 25) by ONE larger (3)

 

2 x 3 = 6

 

Stick the 6 in front of the 25 and you have your answer...

 

625

 

Still not convinced?

 

Try squaring 35...

 

You know your answer will end in 25...

 

Now, multiply the first digit (the 3 in 25) by ONE larger (4)

 

3 x 4 = 12

 

Stick the 12 in front of the 25 and you have your answer...

 

1225

 

 

 

 

 

 

 

Quick Calculations - Use Half and Double

 

 

                                           X        


Work smart, not hard!

Double the...

... to...

 and halve the ...
 
 
 

... to...

 

 

100 X 8 = 800. Done!

 

Use "7" as your "Key"

Try this trick for multiplying two 2 digit numbers under 20. For example...

First off, make sure the larger number is on top.

Then think of the number 7. Well, the shape of it, anyway.

Now ADD 13 and 2 and stick a zero on the end.

Now cover up everything in the left (or 10's) column.

Now ADD 150 and 6 and you get 156

Done!

Percent Video (Type 5)

Percent Video (Type 5)

I have identified at least 5 distinct types of percent questions. (There may be more...) These include...

1) One number expressed as a % of another

2) Finding a certain % of a given number

3) (For want of a better title) The good old "650 is 15 % of what number" type of question.

4) Percent change

5) Increasing or decreasing a number by a given percentage

 

Here's the link for the 5th of 5 videos in a series on percent questions.

Percent Video (Type 2)

Percent Video (Type 2)

I have identified at least 5 distinct types of percent questions. (There may be more...) These include...

1) One number expressed as a % of another

2) Finding a certain % of a given number

3) (For want of a better title) The good old "650 is 15 % of what number" type of question.

4) Percent change

5) Increasing or decreasing a number by a given percentage

 

Here's the link for the 2nd of 5 videos in a series on percent questions.

Percent Video (Type 1)

I have identified at least 5 distinct types of percent questions. (There may be more...) These include...

1) One number expressed as a % of another

2) Finding a certain % of a given number

3) (For want of a better title) The good old "650 is 15 % of what number" type of question.

4) Percent change

5) Increasing or decreasing a number by a given percentage

 

Here's the link for the first of 5 videos in a series on percent questions.