International time is based on the time in Greenwich, England, which is in time zone 0. There are twelve time zones to the west and twelve times zones to the east of time zone 0. As one moves to the east of time zone 0, 1 hour is added for each time zone. As one moves to the west of time zone 0, 1 hour is subtracted for each time zone. New York is 5 times zones to the west of Greenwich, and Finland is 2 time zones to the east of Greenwich. When it is 9 A.M. on Tuesday in Finland, what time is it in New York? 4 A.M. on Monday 7 A.M. on Tuesday 2 A.M. on Tuesday 4 P.M. on Tuesday 1 Sorry, that's not right. You didn't count the extra time zones to get to Greenwich. The correct answer is 2 A.M. on Tuesday. The student probably computed 8 time zones to the east of Finland and forgot about the 2 time zones to Greenwich. 2 Sorry, that's not right. You got the time in Greenwich, but now you have to find the time in New York! The correct answer is 2 A.M. on Tuesday. The student computed Greenwich time. 3 Correct, good job! Student has answered correctly. 4 Sorry, that's not right. You needed to subtract instead of add, because the time in New York is always earlier than Finland. The correct answer is 2 A.M. on Tuesday. The student added 7 to Finland's time, instead of going 7 hours earlier. ModelArithmetic VerbalRuleArithmetic