Math and timing , tricks and more...

[Awuah29]

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Hey guys,

In order to save time on math, do you guys let say write the problems down and then solve them. I mean it sounds silly , because you loose time doing that, but it's just for better visualization. You know how they use to teach us, write down what you 've been giving and solve. Aren't you losing time?

Example: Solve the fractions 17/4 +26/29 . Ok, now instead of writing this fractions on paper again just find denominator and numerator and solve right away. Don't loose time by writing the fractions again , because you have it write on screen. I have been doing this and this is the reason why I run out of time in math. Anyone struggling with it too that you are tempted to write the problems down again.

Bodybldg Doc, Lonely Sol , DDS Dakoo ( thanks for your input see thread math dummy) , .... Jackbauer and the rest of the Sdn family
Need your input please. 😕

Someone mentioned a book called math tricks and shortcuts, but can't find that thread

 

[BodybldgDoc]

Hey guys,

In order to save time on math, do you guys let say write the problems down and then solve them. I mean it sounds silly , because you loose time doing that, but it's just for better visualization. You know how they use to teach us, write down what you 've been giving and solve. Aren't you losing time?

Example: Solve the fractions 17/4 +26/29 . Ok, now instead of writing this fractions on paper again just find denominator and numerator and solve right away. Don't loose time by writing the fractions again , because you have it write on screen. I have been doing this and this is the reason why I run out of time in math. Anyone struggling with it too that you are tempted to write the problems down again.

Bodybldg Doc, Lonely Sol , DDS Dakoo ( thanks for your input see thread math dummy) , .... Jackbauer and the rest of the Sdn family
Need your input please. 😕

Someone mentioned a book called math tricks and shortcuts, but can't find that thread

It really does not take that much time to rewrite it on paper. For math problems its always a good idea to write out things concisely because you dont want to lose track of the mental math in your head and have to start over. That will only end up costing you more time in the process.
Just my 2 cents.

 

[Streetwolf]

17/4 +26/29

4*26 + 17*29 / 4*29

That's the trick...

A/B + C/D = (BC + AD)/BD

You can worry about reducing afterwards.

 

[Awuah29]

17/4 +26/29

4*26 + 17*29 / 4*29

That's the trick...

A/B + C/D = (BC + AD)/BD

You can worry about reducing afterwards.

Streetwolf you are awesome !!Where did you get this math trick from ???
I have tried your approach and its much faster.

Anyone has another short cut? Keep this thread alive . Another notorius math problem is like 7/6 4/8; 2/9 ; 2 etc... Which one is the smallest.

Do you guys cross multiply or what??

 

[Streetwolf]

Do the 'heart' trick:

2/3 versus 4/9:


2 ***** 4
_ versus _

3 ***** 9


Start a line at both the 3 and the 9 (the denominators). Draw them straight up to the OPPOSITE numerator (so the 3 goes to the 4 and the 9 to the 2). Bring the lines around on that side (the numerator side) and down below that fraction. Write the product.

So for the above you would have 18 (9*2) below 2/3 and 12 (3*4) below 4/9. Now fill in a greater than, equal to, or less than sign. Whatever direction it faces is the SAME as the fraction relationship. In this case 18 > 12 so 2/3 > 4/9.

And for the other 'trick' above, it's just simple math: A/B + C/D = A/B (D/D) + C/D (B/B) = AD/BD + CB/BD = (AD + BC)/BD.

 

[dentstd]

Do the 'heart' trick:

2/3 versus 4/9:


2 ***** 4
_ versus _

3 ***** 9


Start a line at both the 3 and the 9 (the denominators). Draw them straight up to the OPPOSITE numerator (so the 3 goes to the 4 and the 9 to the 2). Bring the lines around on that side (the numerator side) and down below that fraction. Write the product.

So for the above you would have 18 (9*2) below 2/3 and 12 (3*4) below 4/9. Now fill in a greater than, equal to, or less than sign. Whatever direction it faces is the SAME as the fraction relationship. In this case 18 > 12 so 2/3 > 4/9.

And for the other 'trick' above, it's just simple math: A/B + C/D = A/B (D/D) + C/D (B/B) = AD/BD + CB/BD = (AD + BC)/BD.

The LCD trick, as Streetwolf suggested, isn't really a trick. It's basic computation of the LCD. It's what everybody does, written in factored form. The "heart trick" seems quite useful, thou. I looked at it and asked myself, is that really true? Does it always work? Then I came up with a proof for it, so yes... it always works. Nifty tool to have for fraction comparison questions. Kudos.

 

[Streetwolf]

It works the EXACT SAME WAY as the first 'trick' in this thread. It gives you the numerators of both fractions as though both fractions had their common denominators (but not necessarily LCDs) computed. So in my example a common denominator is 3*9 (which isn't the LCD - that would be just 9). So for the left fraction you multiply top and bottom by 9. That is, the numerator is multiplied by 9. So your numerator becomes 2*9 = 18. The second fraction becomes 4*3 = 12. So your two fractions are 18/27 and 12/27. My 'heart trick' will just immediately give you the two numerators of these two fractions. Obviously since the denominators are the same, you can compare the two.

 

[EnviroDentist]

Very cool, can anyone do a 3 way heart trick?

 

[Lonely Sol]

Does anyone know a way to figure out when order matter or when order doesn't matter?

Most of the time, I can but sometimes, it kinda confusing!

 

[EnviroDentist]

Does anyone know a way to figure out when order matter or when order doesn't matter?

Most of the time, I can but sometimes, it kinda confusing!

Could you please clarify what you mean.

 

[Streetwolf]

Very cool, can anyone do a 3 way heart trick?

For each fraction, write below it the product of that fraction's numerator multiplied by the other two fractions' denominators. Then compare.

 

[dentstd]

For each fraction, write below it the product of that fraction's numerator multiplied by the other two fractions' denominators. Then compare.

I think he was referring to a 3some.
...3-way love.

 

[Streetwolf]

I think he was referring to a 3some.
...3-way love.

You never know on these forums if it's sexual or not 😛