4. 18·7 106·7-107·6 180-120:5:6 17·8 203·4-204·3 210-140·5:7 19·6 150·6-160·5 240-160:5:8

18·7 = 126
17·8 = 136
19·6 = 114
106·7-107·6 = 742 - 642 = 100
203·4-204·3 = 812 - 612 = 200
150·6-160·5 = 900 - 800 = 100
180-120:5:6 = 180 - 24 : 6 = 180 - 4 = 176
210-140·5:7 = 210 - 700 : 7 = 210 - 100 = 110
240-160:5:8 = 240 - 32 : 8 = 240 - 4 = 236