Wang Hong wants to buy twenty-five pairs of shoes, and then buy ten pairs to get two pairs, which means that Wang Hong wants to buy 2 1 pair, and then he can get two pairs, so it's 25 pairs.

Primary school mathematics is to teach children a series of knowledge about number, four operations, the calculation formula of figure and length, unit conversion and so on through textbooks, which lays a good mathematical foundation for junior high school and daily life calculation. Frieden Noel, a Dutch educator, said: "Mathematics comes from reality and must be rooted in reality and applied to reality." [1] Indeed, modern mathematics requires us to observe the world from a mathematical perspective and explain the world in mathematical language. Judging from the mathematics learning psychology of primary school students, the learning process of students is not a passive absorption process, but a reconstruction process based on existing knowledge and experience. Therefore, learning while doing and learning while playing will make children learn more actively. From our educational goal, while imparting knowledge, we should pay more attention to cultivating students' comprehensive ability of observation, analysis and application.