This Research and Development (R&D) development research aimed to produce Mathematics Students Worksheet (LKPD) on the material of Circumference and Area of flat shapes, to find out the response of students to the developed LKPD, to know the response of parents to the eveloped LKPD, and to know the supporting and inhibiting factors in the use of the LKPD. This study uses the Borg and Gall model with 10 stages that must be passed. The instrument in this study were interviews, tests, and questionnaires. The questionnaire instrument used was given to expert validation, students, and also students’ parents. The results of the validation carried out by the validator obtained a percentage of 90% with very valid criteria. Because the Covid-19 pandemic is still active, testing of student worksheets (LKPD) is done inline, but in accordance with the Delikan learning steps. The use of LKPD which involves the use of a calculator in it is a new thing for students so that the response given by parents and also students is very positive with parental responses of 88.9% (very good) and student response of 85.8% (very interesting). Supporting and inhibiting factors in its use can alo be addressed properly. Therefore, the Mathematics LKPD material on the circumference and area of flat shapes with Delikan learning using a calculator in fourth-grade students SD UMP Banyumas can be said to be feasible and used as teaching material for parents in accompanying their children to study from home.