Question

80:4 40:2+40
60:3 90:3-10
40:2 60:2-20

Answer 1

80 : 4 = 20
40 : 2 + 40 = 60

60 : 3 = 20
90 : 3 - 10 = 20

40 : 20 = 2
60 : 2 - 20 = 10