第一册(义务教育五年制小学数学)四、11—20各数的认识11—20各数的数学教学.教学的重点应该放在使学生初步理解以“十”作为一个计数单位和了解11—20各数的组成上.因此,教学时要充分运用直观教具,让学生亲自动手进行操作.如教师要学生拿出20根小棒,先一根一根地数,数出10根,用橡皮筋把10根小棒捆起来放在 The first volume (compulsory education five-year primary school mathematics) four, 11-20 understanding of each number of 11-20 mathematical teaching. The teaching should focus on enabling students to initially understand the “ten” as a counting unit and understanding 11-20 the composition of the various numbers.Therefore, teaching should make full use of visual aids, let the students hands-on operation.If the teacher asked the students to come up with 20 small sticks, first a root number, count out 10, Put 10 small sticks together with a rubber band