480 ÷ 10 = 48
360 ÷ 30 = 12
(480÷2)÷(10÷2)=
(360×□)÷(30×9)=12
(480÷5)÷(10÷5)=
(360÷□)÷(30÷10)=12
20÷5=4
16÷8=2
(20×6)÷(5×□)=4
(16×□)÷(8×3)=2