tolong bantu jawab no 4-7 pake cara

Maaf kalo ada yg salah... yg nomer 6 kurang tau hehe

5. 4-2,47=1,53=B
6.(79/12+13/36):175/72
=(237/36+13/36):175/72
=250/36:175/72
=18000/6300
=180/63:3
=60/21:3
=20/7
=2 6/7=a

Semoga bermanfaat