Tiny Basic...

 
Sequence
Assignment
Conditional
Iteration
Subroutines
Input/Output
 
440 GOSUB 200
450 PRINT "The square root of ",N," is
200 REM Newton's method to find the squ
210 LET L=1
230 LET R=(L+H)/2
250 IF M=N THEN RETURN
270 IF M<N THEN GOTO 300
280 LET H=R
290 GOTO 310
300 LET L=R
310 GOTO 230