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#1 Matt subtracted 1.9 from 20.8 and got 1.8. Explain why this is not reasonable?

#2 Explain why it is easier to find 10 minus 1.9 mentally than with paper and pencil.

#3 On May 27, 2001, a high school student ran a mile in 3 minutes 53.43 seconds. This broke the previous U.S. record of 3 minutes 55.3 seconds set in 1965. The world record in 2001 was 3 minutes 43.13 seconds.

How much faster is:

the 2001 U.S. record than the 1965 U.S. record?

the world record than the 1965 US record?

the world record than the 2001 US record?

Please show step by step. Thanks.

Tim -- please attempt to solve these problems yourself.

i was in 5th grade last year and believe me its EASIER than you will think it is!! ;)

Well Tim,
It's actually very easy if you think abou it :)

No. 1
- Is obviously not reasonable right?
The real answer is really 8.9, very diff from 1.8 right?

Try doing the rest on your own and if you need any help just let us all know :) I am sure we will all be able to help!