with trace
trace(1)

-- Tutorial - evaluate simple expressions

-- To run this tutorial, keep pressing the Enter key 
-- to execute the next statement, and the F1 and F2
-- keys to flip between the main screen and this trace screen.

-- Step 1 - We can use the question mark (?) to print
-- the value of any expression on the screen. Let's
-- calculate 2+2
? 2 + 2
-- Press F1 then F2 to see the result printed on the screen.

-- Let's try something a bit harder:
? 3 * 3 * sqrt(16)
-- Press F1 then F2 to see the result (and the previous result)
-- printed on the screen.

-- Notice that multiply has higher precedence than addition:
? 2 * 3 + 4 * 5


