2021+100=
102﹣18=
25×24=
+=
0.26-0.22=
2.74﹣1.4=
3.6÷2=
×=
6.4÷80%=
15×=
树高/m
2
3
6
影长/m
0.4
0.6
1.2
□+□=□ □-□=□