《数学课程标准》明确指出:要重视口算,加强估算,提倡算法多样化。在小学数学教学中强化估算,不仅是因为信息高速扩张对小学生计算方法的选择和计算结果的合理性提出了更高要求,也是计算工具快速便捷和普遍采用对小学生大数目笔算要求有所降低的客观反映。更为重要的是,借助 “Mathematical Curriculum Standards” clearly states: we should attach importance to port count, strengthen the estimation, to promote the diversity of algorithms. In primary mathematics teaching to strengthen the assessment, not only because of the rapid expansion of information on the choice of computational methods for primary school students and the reasonableness of the calculation results put forward higher requirements, but also the computational tools quickly and conveniently and universally adopted for a large number of primary school students reduced requirements Objectively reflect. More importantly, with help