When students did experiments, we prepared ideal numbers sheets for this research. Students were allowed to refer to the sheets freely. And we analyzed students' way of learning in the class. We conducted analysis using ideal numbers sheets situation, purpose, effect, and necessity as points of view. As a result we got following things. Students used the sheets positively, but they often used them after the experiment. And they didn't use them from the beginning. Students used the sheets in order to confirm whether their results were right or not. Students used the sheets to confirm. And when the number was wrong, they did the experiment again. Students felt that using the sheets removed their uneasiness. And they think it is easy to learn. Students think using the sheets is good. When they compare ideal numbers and measurement numbers, they can confirm numbers. And they can do experiments again. When the number is correct, they keep studying.