404,991
PEMDAS
Multiplication comes before subtraction
900x450=405,000
405,000-9=404,991
Rational number: Whole number isn't likely, negative integer isn't change, rational number is most likely, irrational number is not possible for cash change.
21 + 15 = 36
36 x 3 = 108
Their father donated $108 to charity
The answer to this problem is one because nine times one equals nine which the answer is still nine
