Fill in the missing operators: 4 [] 7 = 28 55 [] 40 = 15 4 [] 3 = 12

We need to find an operator that, when applied to 4 and 7, results in 28. The multiplication operator satisfies this condition: 4 * 7 = 28.

We need to find an operator that, when applied to 55 and 40, results in 15. The subtraction operator satisfies this condition: 55 - 40 = 15.

We need to find an operator that, when applied to 4 and 3, results in 12. The multiplication operator satisfies this condition: 4 * 3 = 12.