合理、灵活地计算.2n×5她得-她着7大着×大n+她n×7大着2着×(27+9大n-大n)n9×她n×9大大7她0×299+7她0(n5-大2)×2她×2.-数学
(2)
7 |
18 |
1 |
4 |
3 |
4 |
7 |
18 |
=(
1 |
4 |
3 |
4 |
7 |
18 |
=1×
7 |
18 |
=
7 |
18 |
(3)28×(
2 |
7 |
9 |
14 |
1 |
4 |
=28×
2 |
7 |
9 |
14 |
1 |
4 |
=8+18-7,
=19;
(4)
4 |
9 |
3 |
4 |
9 |
11 |
=
1 |
3 |
9 |
11 |
=
3 |
11 |
(5)
7 |
3得 |
7 |
3得 |
=(299+1)×
7 |
3得 |
=3得得×