Another example of plotmath
plotmath is very powerful but also not very simple to use. See ?plotmath Here is another example of formatting: > plot(1:100,main="ABCD",cex.main=1.3) > a=100; b=10 > mtext(bquote(bold(.(formatC(1.2*a,decimal.mark=",",digits=2,format="f")))~" series "~bold(.(formatC(b, digits=0,format="f")))~" items")) > text(x=1, y=50, bquote(bold(.(formatC(1.2*a,decimal.mark=",",digits=2,format="f")))~" series "~bold(.(formatC(b, digits=0,format="f")))~" items"), pos=4) The result is: Some explanations: ~ is a linker between two objects with a space: text(x=1, y=50, bquote("a"~"b"), pos=4) * is a linker between two objects without a space: text(x=1, y=50, bquote("a"*"b"), pos=4) use \" between " to show the " character: text(x=1, y=50, bquote("\"a\""*"\"b\""), pos=4)