阅读程序，填写对应的输出结果

cout << 2.1 + 3.2 << endl;

{{ input(1) }}

cout << 5.5 - 6.0 << endl;

{{ input(2) }}

cout << 10.0 * 3.0 << endl;

{{ input(3) }}

cout << 5.0 / 2.0 << endl;

{{ input(4) }}

5.cout << 100.00 * 30000000.0 << endl;

{{ select(5) }}

• 3000000000
• 3e+09
• 3e-09

6. cout << 4.0 / 100000000 << endl;

{{ select(6) }}

• 4e-08
• 0.00000004
• 0.0000004