用简便方法计算:18.9×178.178+0.49—17.8×189.189
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/27 18:38:24
![用简便方法计算:18.9×178.178+0.49—17.8×189.189](/uploads/image/z/27914-50-4.jpg?t=%E7%94%A8%E7%AE%80%E4%BE%BF%E6%96%B9%E6%B3%95%E8%AE%A1%E7%AE%97%EF%BC%9A18.9%C3%97178.178%2B0.49%E2%80%9417.8%C3%97189.189)
用简便方法计算:18.9×178.178+0.49—17.8×189.189
用简便方法计算:18.9×178.178+0.49—17.8×189.189
用简便方法计算:18.9×178.178+0.49—17.8×189.189
18.9*178.178+0.49一17.8*189.189
=189*17.8178+0.49一17.8*189.189
=189*(17.8+0.0178)+0.49一17.8*(189+0.189)
=189*17.8+189*0.0178+0.49一17.8*189—17.8*0.189
=189*0.0178+0.49—17.8*0.189
=0.189*17.8+0.49—17.8*0.189
=0.49