How to calculate price of inputed quantity

Question

i want to know how to calculate how much the item cost when u buy multiple of it inputing the quantity in a text box and computing its total the total is in a text box.

ex:
bread $5: 4
soda $1: 5

total: $25

Answer 1

variable for bread quanity
variable for soda quantity
variable for bread price
variable for soda price
variable for total

total equals
(bread price multiplied by bread quantity)
+ (soda price multiplied by soda quantity)