Append string with variable

I'm a java guy coming over to Objective-C. In java, to add a variable to a string you'd have to do something along the lines of:

someString = "This string is equal to " + someNumber + ".";

I can't figure out how to do it in Objective-C though. I have an NSMutableString that I'd like to add to the middle of a string. How do I go about doing this?

I've tried:

NSString *someText = @"Lorem ipsum " + someMutableString;
NSString *someText = @"Lorem ipsum " + [someMutableString stringForm];

and a few other things, none of which seem to work. Also interchanged the +s with ,s.