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### Hitting the Ball

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Date: 03/11/97 at 21:41:04
From: Jillian Mamey
Subject: Math word problems and others

Katie hit the ball 742 times on Monday, 267 times on Tuesday, and 847
times on Wednesday. How many times did she hit the ball in three days?
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Date: 03/12/97 at 15:24:53
From: Doctor Mike
Subject: Re: Math word problems and others

Dear Jillian,   Let me guess what sport.  It could be tennis or ping-
pong, maybe volleyball, but certainly not baseball.

These are pretty big numbers for adding, but let's try it.

742
267
+ 847
-----
6

This is the way I would start.  I add up everything I see in the
"ones" column.  I see a 2 and two 7s, and that adds up to 16.  I
see that 16 is 10+6 , and I will write the 6 down right now and
save the 10 for a little later.  REMEMBER IT, OKAY?

742
267
+ 847
-----
56

Next I add up everything in the "tens" column.  I see a 4, a 6,
and another 4.  I add those up and get 14.  I get 14 WHAT?
I get 14 tens because that is what I am adding up now.  I told you
to remember something.  Did you?  Good.  There is one ten left
over from when we were doing the ones column, so we will use that
now.  That means that instead of 14 we really have 15 tens.  Now,
15 tens is 10 tens plus 5 more tens, and I will write the 5 down
right now and save the 10 tens (by the way, 10 tens is a hundred,
right?) for a little later.  REMEMBER THIS ONE TOO, OKAY?

742
267
+ 847
-----
1856

Finally I add up everything in the "hundreds" column.  I see a 7,
a 2, and an 8, which add up to 17 hundreds (we are adding up the
hundreds now).  Put that together with the one hundred (you did
REMEMBER that 10 tens, didn't you!) and you get 18 hundreds.  You
probably know that 18 hundred (1800) is the same as one thousand
plus 8 hundred (1000 + 800).  That's why in the final answer above
you get that "1" in the "thousands" place in the answer, even though
all 3 numbers that we added were less than 1000.  Hey!  We're done.

I hope this helps. It might be good to rest up from all that hitting.
Maybe Katie should concentrate on stamp collecting for a few days.

-Doctor Mike,  The Math Forum
Check out our web site!  http://mathforum.org/dr.math/
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