= = 4=
3 0.875
=
2分,3分,4分,…各能写多少个字?
写字时间/分
1
2
3
4
…
写字数量/个
15
①1204+879+121
②74×60%+×25+0.6
③1.2÷×(0.6﹣)
④×[﹣(+)]