Rational number addition prompt:
1. Add two numbers with the same sign, take the same sign, and then add the absolute values.
2. Add two numbers with different signs, take the sign of the addend with larger absolute value, and subtract the number with smaller absolute value from the number with larger absolute value.
Tips for rational number subtraction:
1. Subtracting a number equals adding the reciprocal of this number.
2. Symbolically: a-b=a+(-b)
Tips for rational number division:
Divide two numbers, the same sign is positive, the different sign is negative, and divide by the absolute value.