Variables and Assignment Statements
Read this chapter, which covers variables and arithmetic operations and order precedence in Java.
26. Arrange what you want with Parentheses
Answer:
+24 + 3 * -4
------
+24 + -12
-----------
12
The first + is a unary plus, so it has high precedence and applies only to the 24.
The - is a unary minus, so it applies only to the 4.
Next in order of precedence is the *, so three times negative four is calculated
yielding negative twelve.
Finally the low precedence + combines the positive twenty four with the negative twelve.
Arrange what you want with Parentheses
To show exactly what numbers go with each operator, use parentheses. For example
-1 * ( 9 - 2 ) * 3
means do 9 - 2 first. The ( ) groups together what you want done first. After doing the subtraction, the ( 9 - 2 ) becomes a 7:
-1 * 7 * 3
Now follow the left-to-right rule for operators of equal precedence:
-1 * 7 * 3
------
-7 * 3
--------
-21
Question 26:
What is the value of each of the following expressions?