A simple Dictionary class for Numbers.
메서드
Add the given number to the value currently stored at the given key. The sum then replaces the value previously stored in the Dictionary.
Subtract the given number from the value currently stored at the given key. The difference then replaces the value previously stored in the Dictionary.
Multiply the given number with the value currently stored at the given key. The product then replaces the value previously stored in the Dictionary.
Divide the given number with the value currently stored at the given key. The quotient then replaces the value previously stored in the Dictionary.
Return the lowest number currently stored in the Dictionary.
Return the highest number currently stored in the Dictionary.
Return the lowest key currently used in the Dictionary.
Return the highest key currently used in the Dictionary.