1.23

1 million seconds = 277.777778 hours

1 million seconds = 11.5740741 days

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Possible approach:

a) There are 3600s in an hour
b) Eliminating the thousands, we get 1000 / 3.6
c) 3.6 is about half-way between 3 and 4, thus the result is about 
   (1000/3 + 1000/4)/2 ≈  (333+250) = 583/2 ≈ 290
d) About 12 days (240 + 48)

Another approach:

a) There are 3600s in an hour
b) 3600s goes into 10,000s ≈ 3 hours
c) multiply 3 with 100 = 300 hours (since 10,000s is 100 times less than 1,000,000)
d) 24h goes into 30h ≈ 1.2 day
e) multiply 1.2 by 10 = 12 days (since 30h is 10 times less than 300)

Back to Chapter 1.