In the study of proportion knowledge, we can understand the meaning and basic nature of proportion, know solution ratio, see the scale, understand the meaning of positive proportion and inverse proportion, judge whether the two quantities are directly proportional or inversely proportional, and solve relatively easy application problems with proportion knowledge.
In the study of common three-dimensional graphics, we can know the characteristics of cylinders and cones, have a preliminary understanding of the radius and diameter of spheres, and calculate the surface area of cylinders and the volumes of cylinders and cones according to the actual situation. For example, a circular pool requires its floor area to be the bottom area; Require the length of a circle around the pool, that is, find its bottom circumference; To cement the periphery and bottom of the pool, it is to find its surface area (a bottom area plus lateral area); To know how much water a pool can hold, you need to know its volume. It should be analyzed according to the actual situation and specific problems, and should not be confused.
In the study of preliminary statistical knowledge, everyone will read and make composite statistical tables with percentages, understand the drawing method of simple statistical charts, and initially read and draw simple statistical charts.
Finishing and reviewing is a key point of this book. Through systematic arrangement and review, we can deepen our understanding and mastery of the mathematical knowledge learned in primary schools, better cultivate reasonable and flexible computing ability, develop our own thinking ability and spatial concept, and improve our ability to solve simple practical problems by comprehensively applying the learned mathematical knowledge.