Tape-figure is used as one tape or two tapes accoding to the content of problems. In this study, I used it with two tapes. The intention is that I hope students would solve the problems using the same tape-figure. Nevertheless, I do not know whether this model work well as a schema to solve every addition and subtraction word problems. We make sure of the effectiveness to use tape-figure.
Students use tape-figure while lower grades, but from the third grade they use number straight line.
I research the points and what we should consider in teaching tape-figure. So, I thought, they should learn word problems after they have understood the meaning and function of tape-figure to some extent. And I used the first time to practice how to write and use tape-figure. This is a addition-model. As the sample was onle one, it may be not sufficient for students.