The usual arithmeticconversion rules state that first you perform the integer promotions on any integer operands.
常用算术转换规则规定在任意整数运算时首先执行整型提升。
2
As you probably suspect, the integer conversion rank is used to define the rules for expression evaluation. Those rules are named the integer promotions and the usual arithmetic conversions.
就如你可能猜想的那样，整数转换优先级用于定义表达式求值的规则。这些规则叫做整型提升和常用算术转换。
3
PHP also has automatic type conversion for arithmetic operations.