①83×4=
②264×5=
③608×4=
④350×9=
⑤996+96=
⑥72×5=
35+7=
62-8=
53+26=
23×3=
31×2=
700×4=
41+29=
5+24=
19+4=
80-43=
3000×0=
75-12=
36+9=
53-30=
72-65=
170+130=
280-160=
+=
-=
+-=
59+36= 21×4= += 1-=
①378×3=
②507×4=
③250×6=
④*467+378=
⑤687+147=
⑥*604-578=
①600-289=
②*389+172=
③*739+286=
④350+220=
⑤*405-223=
⑥*810-467=
①582+89=
②985+67=
③689+507=
④*1000-235=
⑤*582+139=
(用两种方法解答1.求出面积再比较;2.用“比”的知识来解题,先求半径之比,再求面积之比.)