數學題.......

A.1 If -$100 represents the price of a camera lowered by $100 , how do you represent a decrease in price of a camera by $200 ?

-$200, so easy...
B.In each of the following , use a directed number to represent the underlined phrase , and state the meaning of 0 .

B.1 The diver is ( 3 m below ) sea level .
-3m
0 represents sea level

B.2 The Octopus card was ( $4.1 overdrawn ) .
-$4.1
0 represents that value of the Octopus card is zero


*請用英文作答!!


C.1 If +$200 means a deposit of $200 into a bank account , what does -$300 mean ?

-$300 means overdraw of $300

*請用英文作答!!