a.\(\frac{327.412+400}{328.412-12}=\frac{327.412+400}{\left(327+1\right).412-12}=\frac{327.412+400}{327.412+412-12}=\frac{327.412+400}{327.412+400}=1\)
b.\(\frac{1234.567-667}{1234.566+567}=\frac{1234.\left(566+1\right)-667}{1234.566+567}=\frac{1234.566+1234-667}{1234.566+567}=\frac{1234.566+567}{1234.566+567}=1\)