Bash ==== <!-- language-all: lang-bsh --> Since this is a [tag:popularity-contest], I guess I should use a long-winded method... For people who don't know Bash: `$((...expr...))` is a syntax to evaluate arithmetic expressions. `$(bc<<<...expr...)` does the same using the `bc` command-line calculator. v=2 #v is 2 v+=2 #v is 4 v=$(($v*5)) #v is 20 v=$(($v-16)) #v is 4 v=$(bc<<<"sqrt($v)+2") #v is 4 (sqrt(4) is 2) v=$(bc<<<"$v/4+3") #v is 4 (4/4 = 1) echo '2+2=' $v #So v is 4...? Output ---- 2+2= 5 Explanation ------ >! The second line concatenates v and 2 instead of adding them, to make 22.<br /> >! Actual explanation:<br />` >! v=2 #v is 2 >! v+=2 #v is 22 >! v=$(($v*5)) #v is 110 >! v=$(($v-16)) #v is 94 >! v=$(bc<<<"sqrt($v)+2") #v is 11 (by default, bc rounds to integers) >! v=$(bc<<<"$v/4+3") #v is 5 (11/4 is 2 with rounding) >! echo '2+2=' $v #TADAAAM`