invalid left hand side in assignment c#

Error CS0131: the left-hand side of an assignment must be a variable, property or indexer. How to fix this?

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Error CS0131: the left-hand side of an assignment must be a
In C# (and most if not all other languages) there is something called an LValue and an RValue: when you do an assignment you always have an LValue on the left of the equals sign and an RValue on the right. The LValue is where the value is to be stored, and the RValue is the value to store into it.
c#
Code is returning: "The left-hand side of an assignment must be a variable, property or indexer" I'm still new to C# (coming from python), but I understand this issue, however I've got no clue how to fix it. I essentially want to have input initially equal x round x each cycle and multiply that rounded number by input y:
{solved} ReferenceError: Invalid left-hand side in assignment
When you compare something you need to use three equals signs. So if you want to say 8 * 2 is equal to 16 you would show it 8*2===16