一、加强口算训练。要使学生口算得正确而又迅速,关键在于让他们掌握口算方法,并且经常练习,特别是要加强一位数与15、25相乘的训练。因为在多位数的除法中,除以15、25的数,要求最好能用口算试商,这样,可以大大减少试商次数,提高试商速度。在这里,就应该为它作些口算准备,以打下扎实的基础。同时,口算的练习要注意经常练,要持之以恒,才能收到良好的效果。二、先易后难,逐步提高。在一位数乘两位数的 First, to strengthen oral training. The key to making the students correct and quick is that they should be familiar with the method of calculating their words and how to practice them regularly. In particular, one-digit training multiplied by 15 and 25 should be stepped up. Because in the multi-digit division, divided by the number of 15,25, asked the best use of port count test operators, so that you can greatly reduce the number of trial, to speed up the trial. Here, we should make some preparations for it in order to lay a solid foundation. At the same time, the exercise of mouth count should pay attention to regular practice, to persevere, in order to receive good results. Second, the first easy post-disaster, and gradually increase. In one digit by two digits