1.直接写出得数。
$491÷7\approx$ $322÷8\approx$ $317÷8\approx$ $819÷2\approx$
$558÷8\approx$ $358÷3\approx$ $699÷2\approx$ $961÷3\approx$
$805÷9\approx$ $721÷9\approx$ $904÷9\approx$ $211÷7\approx$
$699÷7\approx$ $148÷3\approx$ $397÷8\approx$ $419÷6\approx$
$702÷7\approx$ $238÷6\approx$ $716÷8\approx$ $282÷4\approx$
$632÷9\approx$ $121÷4\approx$ $447÷9\approx$ $221÷2\approx$
$238÷3\approx$ $536÷9\approx$ $143÷7\approx$ $639÷2\approx$
$304÷3\approx$ $353÷7\approx$ $178÷9\approx$ $241÷2\approx$
$598÷3\approx$ $643÷8\approx$ $181÷6\approx$ $681÷2\approx$
$179÷3\approx$ $811÷9\approx$ $749÷5\approx$ $261÷2\approx$
$279÷4\approx$ $452÷5\approx$ $159÷4\approx$ $459÷2\approx$
$297÷5\approx$ $281÷4\approx$ $548÷5\approx$ $991÷3\approx$

1.
$491÷7≈70$ $322÷8≈40$ $317÷8≈40$ $819÷2≈410$
$558÷8≈70$ $358÷3≈120$ $699÷2≈350$ $961÷3≈320$
$805÷9≈90$ $721÷9≈80$ $904÷9≈100$ $211÷7≈30$
$699÷7≈100$ $148÷3≈50$ $397÷8≈50$ $419÷6≈70$
$702÷7≈100$ $238÷6≈40$ $716÷8≈90$ $282÷4≈70$
$632÷9≈70$ $121÷4≈30$ $447÷9≈50$ $221÷2≈110$
$238÷3≈80$ $536÷9≈60$ $143÷7≈20$ $639÷2≈320$
$304÷3≈100$ $353÷7≈50$ $178÷9≈20$ $241÷2≈120$
$598÷3≈200$ $643÷8≈80$ $181÷6≈30$ $681÷2≈340$
$179÷3≈60$ $811÷9≈90$ $749÷5≈150$ $261÷2≈130$
$279÷4≈70$ $452÷5≈90$ $159÷4≈40$ $459÷2≈230$
$297÷5≈60$ $281÷4≈70$ $548÷5≈110$ $991÷3≈330$

2.估一估，连一连。
$491÷7$
$558÷8$
$805÷9$
$699÷7$
$702÷7$
商大于80
商小于80
$632÷9$
$338÷5$
$186÷2$
$558÷7$
$179÷3$

2.
连线结果见：
商大于80：$805÷9$、$699÷7$、$702÷7$、$186÷2$、$338÷5$
商小于80：$491÷7$、$558÷8$、$632÷9$、$558÷7$、$179÷3$