Introduction

two-dimensional shape. (Also called “shape”.)A shape having length and width but not depth.Two-dimensional shapes include circles, triangles,quadrilaterals, and so forth. See also threedimensionalfigure.unitizing. The idea that, in the base ten system,10 ones form a group of 10. This group of 10 isrepresented by a 1 in the tens place of a writtennumeral. Likewise, 10 tens form a group of 100,indicated by a 1 in the hundreds place.Venn diagram. A diagram consisting of overlappingand/or nested shapes, used to show what twoor more sets have and do not have in common.See also graphic organizer.Parallelograms squaresrectanglesrhombusesword wall. (Also called “math word wall”.) A listof words, grouped in a logical way (alphabetically,by strand, by concept) and displayed prominentlyin the classroom, that teachers use to help studentsbecome familiar with mathematics vocabulary.zero property of multiplication. The notionthat the product of a number multiplied by 0 is 0.zone of proximal development. The levelof understanding immediately above a person’spresent level. If instruction is within a student’szone of proximal development, new knowledgecan be connected with prior knowledge, and thestudent can be helped to develop more complex andencompassing understanding. If instruction is belowthe zone of proximal development, the studentdoes not gain new knowledge or understanding.If instruction is beyond the zone of proximaldevelopment, the student has insufficient priorknowledge to which new ideas can be connected.vertical format. In written computation, a formatin which numbers are arranged in columns. Seealso horizontal format.23+48Vertical format102 A Guide to Effective Instruction in Mathematics, Kindergarten to Grade 6 – Volume One