Using textfield content for math

Question

// set variable as numbers
var monthly_num:Number = 0;
var ttl_num:Number = 0;
var ttl_rev_num:Number = 0;
// user-entered numbers from an Input textfields
monthly_num = monthly_txt.text;
ttl_num = ttl_txt.text;
// Multiply two user-entered number together to get new
result
ttl_rev_num = ttl_num*monthly_num;
// Attempts to assign numbers typed into textfields to
numeric variables causes errors.
1067: Implicit coercion of a value of type String to an
unrelated type Number.

Answer 1

you must 'cast' the text string as a number as in:
monthly_num = Number(monthly_txt.text);
ttl_num = Number(ttl_txt.text);
ttl_rev_num = ttl_num*monthly_num;