用简便方法计算72+89-72+89 628-155-45+72
来源:学生学帮网 编辑:学帮网 时间:2024/07/06 16:20:39
用简便方法计算72+89-72+89 628-155-45+72
72+89-72+89
=72-72+(90-1)*2
=180-2
=178
628-155-45+72
=(628+72)-(155+45)
=700-200
=500
用简便方法计算72+89-72+89 628-155-45+72
72+89-72+89
=72-72+(90-1)*2
=180-2
=178
628-155-45+72
=(628+72)-(155+45)
=700-200
=500