部分教材中编排的估算题都是接近整十数、整百数的特殊数据,这让教师和学生造成错觉,认为只有这样的数据才能估算,其余的都不能估算,同时也造成了对估算方法的误解,认为估算的方法就是把数据估成接近整十数、整百数来计算,或者误认为两个估和一个估的情况中多估几个几情况相同,导致学生机械地估、 Some of the textbooks are arranged in the estimation of the problem are close to the whole number of ten, hundreds of special data, which makes teachers and students create the illusion that only such data can be estimated, the rest can not be estimated, but also resulted in the estimation method Misunderstanding, that the method of estimation is to estimate the data close to the whole number of ten, the whole hundred to calculate, or mistaken for two estimates and an estimate of the situation in the estimation of a few more than the same situation, resulting in mechanical assessment,