Math Fluency: Accuracy Versus Speed in Preoperational and Concrete Operational First and Second Grade Children

Cognitive abilities as well as math fluency play an important role in mathematical skills. Understanding the relationship between cognitive abilities and mathematical skills is imperative to teaching effective arithmetic skills. The present study aimed to investigate the relationship between cognitive ability and math fluency with 38 first and second grade elementary aged children. Results demonstrate that preoperational children lacked the speed of concrete operational children but achieved comparable levels of accuracy when completing arithmetic problems.     

亚式股票期权的定价及其在期股激励中的应用

亚式股票期权是当今金融衍生品市场最为活跃的新型期权之一。文章介绍了亚式股票期权的概念,讨论了亚式股票期权的定价公式及应用,并举例说明了亚式股票期权在期股激励中的应用。     

关于等差和等比数列的性质及其应用

对等差和等比数列这个古典代数学的基本内容作了一些较深入的探讨，得到了一系列非常有用的结果，并通过典型例题说明了它们在有关方面的应用。     

Covariation between reading and arithmetic skills from Grade 1 to Grade 7

This study examined the extent to which reading and arithmetic skills show covariation at Grade 1 and at Grade 7, to what extent this covariation is time-invariant or time-specific, and to what extent different antecedents will predict these time-invariant and time-specific portions of the covariation. The reading and arithmetic skills of a total of 1335 Finnish children were assessed at the end of Grade 1 and then again at the end of Grade 7. Phonological awareness, letter knowledge, rapid automatized naming (RAN), counting, and parental education levels were measured in kindergarten; working memory at Grade 1 and nonverbal reasoning at Grade 3. The results showed that reading and arithmetic had a substantial amount of covariation at grades 1 and 7, and that most of the covariation between these grades was time-invariant and could be predicted by RAN, counting, letter knowledge, working memory, and nonverbal reasoning. The time-specific portion of the covariation between reading and arithmetic in Grade 1 was predicted by phonological awareness, letter knowledge, and counting; while time-specific covariation in Grade 7 was predicted by parental education level and nonverbal reasoning.     

三维散乱点的八叉树建模及程序实现

本文根据三维采样点的离散数据,用八叉树方法和与距离成反比加权法的数据插值方法重构地质体的三维模型,详细地论述了八叉树构模的程序算法,同时开发出基于VC 八叉树构模类,并嵌入电磁资料处理系统软件,为电磁资料处理的三维可视化提供了便利。     

基于可视化语言的图像表面控制

许多复杂的图像处理需要结合其他的图像处理算法才能实现,因此,主要介绍了计算机图像处理中的图像草稿效果算法,并在该算法的基础上利用VB6.0语言所提供的图像处理功能实现了图像表面的草稿效果。     

Enhancing arithmetic in pre-schoolers with comparison or number line estimation training: Does it matter?

Children's intuitive understanding of number, i.e. number sense, is associated with individual differences in mathematics achievement. To investigate the causal association between number sense, traditionally assessed with comparison or number line estimation tasks, and mathematics achievement, often assessed with an arithmetic test, an intervention study was conducted that aimed at training either comparison or number line estimation skills. We contrasted a comparison and number line estimation training. By doing so, we wanted to address the question which intervention had the largest effect on arithmetic. In addition, such a direct comparison between comparison and number line estimation trainings would allow us to get more insight in the association between both tasks. Participants were 151 five-year-olds that were randomly allocated to either an experimental condition (i.e. comparison or number line estimation) or one of the two control conditions (i.e., active control condition and empty control condition) in a pretest-posttest design measuring number knowledge, (non-)symbolic comparison and number line estimation and arithmetic. The results showed that both comparison and number line estimation trainings had a positive effect on arithmetic. However, the absence of transfer effects from one task to another, also suggested that comparison and number line estimation rely on different mechanisms and probably influence arithmetic through different mechanisms.     

Are first graders' arithmetic skills related to the quality of mathematics textbooks? A study on students’ use of arithmetic principles

A major goal of the first years of schooling is students' development from using counting strategies to using calculation strategies – or even recall – to solve addition or subtraction problems. It requires the perception and usage of arithmetic principles. Although the continued use of counting strategies is problematic for further learning progress, they are frequently used by many students beyond Grade 1. While learning resources possibly play a role in students' development in this field, our knowledge about their impact is limited. In this study we investigated the presented learning opportunities of four different textbooks regarding arithmetic principles in Grade 1, and subsequently the relation to first graders' strategy use by analyzing a one-year dataset of 1614 students from 86 classes. The analyses show differences in the textbooks' quality concerning arithmetic principles as well as a considerable connection to students' strategy use at the end of Grade 1.     

关于高阶等差数列的一个不变量

设｛xn｝n≥0是任意的m阶等差数列，本文证明：对任意的n≥0，（m＋1）阶行列式的值与n无关，因而是这类数列的一个不变量，并且这一结论是一般常系数齐次线性追归数列的一个普遍性质的特例．     

Statistical Tools and Statistical Literacy: The Case of The Average

This article is intended to serve as a starting point for a dialogue regarding the goals of teaching students about averages and how to assess their emerging knowledge.