一、说教材《两位数减两位数退位减》是九年义务教育六年制小学数学第二册第五单元第七节的内容。本节课是在学生学习了２０以内的退位减法、两位数减一位数的退位减法口算、两位数减两位数不退位减法笔算的基础上学习的。本节课是笔算减法的开始 ,也是以后学习多位数笔算减法 First, the teaching material “double-digit double-digit abatement minus” is the content of the seventh section of the fifth unit of the second volume of mathematics of six-year compulsory education six years of compulsory education. This lesson is to learn from the students less than 20 abatement subtraction, two-digit minus one-digit abatement subtraction accounting, two-digit minus two digits based on the absenteeism pen study. This lesson is the beginning of pen and paper subtraction, but also after learning a few digits pen subtraction