Aidan has four cards with +, –, ×, ÷ printed on them. He inserts them between the five numbers 5, 4, 3, 2 and 1 to form the expr
ession 5 + 4 × 3 – 2 ÷ 1, which has the value 15. Emma says: "Aidan put the operation cards in the order +, ×, –, ÷. If I place the operation cards in a different order between the numbers 5, 4, 3, 2, 1, I can make the value equal to 19." In what order did Emma place the four operations?
