Division by zero how do you handle it a select statement

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SQL-Server-2008R2

Dear Expert,

How do you handle division by Zero should it occur so that it doesn't create a problem with
the Select statement

as depicted below

((Q1Y2C - Q1Y1C)*100)/Q1Y1C DIFFCQ1P ,
((Q2Y2C - Q2Y1C)*100)/Q2Y1C DIFFCQ2P ,
((Q3Y2C - Q3Y1C)*100)/Q3Y1C DIFFCQ3P ,
((Q4Y2C - Q4Y1C)*100)/Q4Y1C DIFFCQ4P


These are
Q1Y1C ,
Q2Y1C ,
Q3Y1C ,
Q4Y1C



SELECT BRNNAME, SCORE ,
Q1Y1C , Q1Y2C ,
Q2Y1C , Q2Y2C ,
Q3Y1C , Q3Y2C ,
Q4Y1C , Q4Y2C ,
Q1Y1P , Q1Y2P ,
Q2Y1P , Q2Y2P ,
Q3Y1P , Q3Y2P ,
Q4Y1P , Q4Y2P ,
(Q1Y2C - Q1Y1C ) DIFFCQ1C ,
(Q2Y2C - Q2Y1C ) DIFFCQ2C ,
(Q3Y2C - Q3Y1C ) DIFFCQ3C ,
(Q4Y2C - Q4Y1C ) DIFFCQ4C ,
((Q1Y2C - Q1Y1C)*100)/Q1Y1C DIFFCQ1P ,
((Q2Y2C - Q2Y1C)*100)/Q2Y1C DIFFCQ2P ,
((Q3Y2C - Q3Y1C)*100)/Q3Y1C DIFFCQ3P,
((Q4Y2C - Q4Y1C)*100)/Q4Y1C DIFFCQ4P
FROM YFINAL ORDER BY BRNNAME


Division by Zero

((Q1Y2C - Q1Y1C)*100)/Q1Y1C DIFFCQ1P ,
((Q2Y2C - Q2Y1C)*100)/Q2Y1C DIFFCQ2P ,
((Q3Y2C - Q3Y1C)*100)/Q3Y1C DIFFCQ3P,
((Q4Y2C - Q4Y1C)*100)/Q4Y1C DIFFCQ4P

What I have tried:

On going sql server developmental challenges