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What is 65 Times Ten Million?

Date: 29 Mar 1995 14:40:58 -0500
From: Susan Fisher
Subject: Question about times one million

Dear Dr. Math, 

What is 65 times ten million?  Also, we've had pluses, 
multiples and times. Is there going to be any new things 
after that?

Thanks for trying even if you don't get that one.

                    Eli Golden
                    2nd Grade
                    Hadley School
                    Swampscott, Mass.


Date: 29 Mar 1995 18:21:50 -0500
From: Dr. Ken
Subject: Re: Question about times one million

Hello there!

About your first question:  multiplying by ten million 
isn't as hard as you might think.  First notice that ten 
million is 10,000,000.  When you multiply by a number 
like 10 or 1,000 or something like that, you just take
all the zeroes from one number and stick them on the 
other one.  For instance, 6 x 10 = 60,  57 x 100 = 5700, 
and 65 x 10,000,000 = 650,000,000.  So that's the 

About your second question:  Oh yes, there will soon be 
something new.  I hope I'm not spoiling the surprise.  You 
know how addition and subtraction are opposites?  By 
that I mean if 3 + 5 = 8, then 8 - 5 = 3, and things like 
that.  Well, there's going to be a new operation that you'll
learn that's the opposite of multiplication.  It's called 
"division."  The good part is, if you know how to multiply, 
you'll learn how to divide really fast:  for instance, since 
4 x 5 = 20, 20 divided by 4 is 5.  Does that make sense?  
It'll get a whole lot easier when you do it more.

Thanks for the question!

-Ken "Dr." Math
Associated Topics:
Elementary Multiplication

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