Hitting the BallDate: 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? 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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