Breaking equations down into parts while retaining output

Greetings, I am new to Matlab and have some novice level programming experience. I am working on a lengthy equation that involves a lot of parantheses and it is getting tough to keep them all straight and make sure they're in the right place. I thought it would help if I could break the equation down into smaller parts. To simplify that idea, as an exercise, I made this code below:

syms a rational positive integer
syms b rational positive integer
syms c rational positive integer
syms d rational positive integer
syms atimesb rational positive integer
syms ctimesd rational positive integer
syms MyTotal rational positive integer

eqn = atimesb == a * b
eqn = ctimesd == c * d

eqn = MyTotal == atimesb + ctimesd

I was hoping the output (on the right side in Matlab) for MyTotal would be: eqn = MyTotal = ab + cd

However, the output I'm getting is: eqn = MyTotal == atimesb + ctimesd

Do I need to use a function to get they type of output I'm looking for? Is there any other way than using a function? Can anyone help by showing me an example?

Answer 1

[madhan ravi]

 atimesb = a * b;
 ctimesd = c * d;

 eqn = MyTotal == atimesb + ctimesd

[GratefulLed]

Amazing, thanks so much! It's like learning a new language (actually, it is learning a new language haha)