123456+1234567+?

123456+1234567+? 123456-23456-1+123456+4-1234567=? 12345×123456=?123456×1234567=? 12+123+1234+12345+123456+1234567= (123456+1234567+12345678+123456789)*123456789=? 123+1234+12345+123456+1234567+12345678+123456789 1234+12345+123456+1234567+12345678= 123456×123456-123455×1234567四年级用简便方法算 1+1+12+123+1234+12345+123456+1234567+12345678+123456789 123456,1234567,12345678,123456789添加符号等于一? 1+12+123+1234+12345+123456+1234567+12345678+123456789+987654 12+123+1234+12345+123456+1234567+12345678+123456789+12345678