2. Two digits within100 can be added or subtracted, integer hundreds and thousands can be added or subtracted, and hundreds and dozens can be added or subtracted, which can be estimated according to the actual situation.
3. Know the meaning of division, the names of each part in the division formula, and the relationship between multiplication and division; Can skillfully use multiplication formula to find quotient.
4. Understand the significance of mathematical problems, and realize the close relationship between discovering and asking questions from life and mathematics and daily life. Knowing the function of brackets, I will use brackets in solving problems.
5, can distinguish acute angle and obtuse angle; Initially perceive the phenomenon of translation and rotation, a simple figure will translate horizontally or vertically on the grid paper.