先估一估再列竖式计算31x23
å ä¼°ä¸ä¼°ååç«å¼è®¡ç®31x23
1ãä¼°ç®ï¼
31x23
â30x20
=600
2ãåç«å¼è®¡ç®ï¼
31x23=713