Continue shopping “Understanding Computer Systems” has been added to your cart. Product Price Quantity Subtotal × Start a CoderDojo Club $39 Start a CoderDojo Club quantity $39 × Creating Apps in the Classroom $29 Creating Apps in the Classroom quantity $29 × Understanding Computer Systems $49 Understanding Computer Systems quantity $49 Coupon: Apply coupon Update cart Cart totals Subtotal $117 Total $117 Proceed to checkout