• 1. (2021五上·浚县期中) 脱式计算，能简算的要简算

  ①0.74×99

  ②1.39×6.1+3.9×1.39

  ③2.4×0.7÷2.4×0.7

  ④42.72÷0.48+0.52

  ⑤4.9÷0.25÷0.4