76-58+39=

45-23+49=

93-67+22=

100-64-32=

54+34-25=

78-56+35=

65+29-66=

76-68+49=

54-29+36=

98-67+3 1=

100-36-33=

78-6 1+56=

23+54-60=

76-65+39=

45-23+49=

96-64+32=

100-56-32=

For the calculation of this mixed problem of addition and subtraction, teaching is carried out on the basis of addition and subtraction. Because the order of operation is the same as addition and subtraction, students are allowed to make analogies in teaching. Students can independently apply the pen calculation method they have learned before to solve two vertical questions, and then let them think of vertical questions for simple writing. Finally, the teacher emphasized the points that should be paid attention to in this simple writing.