Pages 47 through 65

Pages 26 through 46

Page 47 – Simplifying Radicals

Page 48 – % of is % of what number

Page 49 – Multiplying powers of pi

Page 50 – Powers of i

Page 51 – If a= b and b = c then 1a = ? c

Page 52 – Sum/Product of the Roots and Discriminate

Page 53 – Log ab=c

Page 54 – Sum of Two Squares 101

Page 55 – Multiplying by number close to 100

Page 56 – Mean or Average

Page 57 – Number of Divisors

Page 58 – Converting square and cubic units

Page 59 – Converting repeating decimals to fractions

Page 60 – Distance and Midpoint of 2 points

Page 61 – Converting n/40 to a decimal

Page 62 -1234..nx9+(n+1)

Page 63 – Sum of consecutive Integers

Page 64 – Mi/Hr=Ft/Sec

Page 65 -Dividing Factorials


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  1. Andrew Wang

    can you show how to do 16!/(8!*8!)


    Andrew Wang

    1. anthony gillespey

      Think of it this way. (16x15x14x13x12x11x10x9x8!)/(8!x8!)= (16x15x14x13x12x11x10x9)/(8x7x6x5x4x3x2x1),cancel 8! from numerator and denominator. After that just start canceling from top and bottom. such as 16/(8×2) cancels. Keep doing that and you should end up with a single whole number answer. In this case 12870 please note that this problem could not be solved mentally for most people.

  2. Math Rocks

    Hello Mr. Gillespy,
    Can you make a video showing how to solve those clock problems? For example, on some ns test, it asks to solve for the acute angle between 5:24 or something like that. The reason I feel a video will help more than a regular explanation is because it is easier to explain visually. Any way that you can reply, I appreciate it.


    1. anthony gillespey

      30H – 11/2 M take the absolute value.

      1. Math Rocks

        Thank you Mr. Gillespy. I have ANOTHER question. How do you divide 34 base 8 by 2 base 8 without changing each to base ten then swithcing it back. Is there a trick for it?

        1. Math Rocks

          By the way, I forgot to say that the answer has to be in base 8

        2. anthony gillespey

          Honestly in this case converting to base 10 then divide by two is very fast. Then back to base 8 is another 2 seconds. That’s the way I would do it. If you wanted to though you would have to know some basic base 8 times tables or convert quickly. Example 2 goes into 3 once remainder 1 bring down 4. 3 goes into 14 base 8 (this is the tricky part) 4 time. Because 14 base 8 is = to 12 base 10. Like is said more work than its worth.

          1. Math Rocks

            thank you.. also thanks for the overflow calc video, it helped me

  3. Beatriz

    Hello, do you know of a math trick to get an approximate answer when multiplying 2 and 3 digits numbers.
    For example: 243X514

    1. anthony gillespey

      Well 243 is reall close to 250 so use the 25’s trick with 512 since its a multiple of 4. so 128000

  4. NERD

    Mr Gillespey is it possible to show how to do overflow on a TI 84 plus CE

    1. anthony gillespey

      The process would be the same but honestly you should move past a ti 84.

  5. Awesome

    How would you do 18×19/23?

    1. anthony gillespey

      I have a new book coming out in days that has this trick in it.Scratch that the book is out now 🙂

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