题目
递等式计算(能简算的要简算)。
①7.8×(4.7-3.627÷0.9)
②3.76÷0.4÷0.25
③7.9+21.21÷2.1
④2×(0.5+0.125)×8
⑤3.7×101
⑥3÷7.5+3÷2.5
答案:①7.8×(4.7-3.627÷0.9) =7.8×(4.7-4.03) =7.8×0.67 =5.226 ②3.76÷0.4÷0.25 =3.76÷(0.4×0.25) =3.76÷0.1 =37.6 ③7.9+21.21÷2.1 =7.9+10.1 =18 ④2×(0.5+0.125)×8 =2×0.5×8+0.125×8×2 =1×8+1×2 =8+2 =10 ⑤3.7×101 =3.7×(100+1) =3.7×100+3.7×1 =370+3.7 =373.7 ⑥3÷7.5+3÷2.5 =0.4+1.2 =1.6