探索图形长方体和正方体
1cm1cm1cm
9cm9cm9cm
9cm9cm9cm
8cm8cm8cm
7cm7cm7cm
6cm6cm6cm
5cm5cm5cm
4cm4cm4cm
3cm3cm3cm棱长三面涂色两面涂色一面涂色没有涂色2cm3cm2cm2cm2cm800081261
4cm4cm4cm棱长三面涂色两面涂色一面涂色没有涂色2cm80003cm812614cm82424
4cm4cm棱长三面涂色两面涂色一面涂色没有涂色2cm80003cm812614cm824244cm4cm8
棱长三面涂色两面涂色一面涂色没有涂色2cm80003cm812614cm8242485cm5cm5cm5cm8365427
9cm9cm9cm
4cm
第一层:1(个)第二层:1+2=3(个)第三层:1+2+3=6(个)第四层:1+2+3+4=10(个)总的个数:1+3+6+10=20(个)