计算题(39*2/7+2/7*4)÷2/7 7/12-(1/4-5/12) 5-3/2*10/21-2/7

问题描述:

计算题(39*2/7+2/7*4)÷2/7 7/12-(1/4-5/12) 5-3/2*10/21-2/7

  (39*2/7+2/7*4)÷2/7
  =(39*2/7+2/7*4)*7/2
  =39*2/7*7/2+2/7*4*7/2
  =39+4
  =43
  7/12-(1/4-5/12)
  =7/12-1/4+5/12
  =(7/12+5/12)-1/4
  =1-1/4
  3/4
  5-3/2*10/21-2/7
  =5-5/7-2/7
  =5-(5/7+2/7)
  =5-1
  =4