问题
解答题
|
答案
（1）4×4.9×25，
=（4×25）×4.9，
=4.9×100，
=490；
（2）
| 5 |
| 6 |
| 3 |
| 4 |
| 1 |
| 6 |
| 4 |
| 3 |
=
| 5 |
| 6 |
| 3 |
| 4 |
| 1 |
| 6 |
| 3 |
| 4 |
=
| 3 |
| 4 |
| 5 |
| 6 |
| 1 |
| 6 |
=
| 3 |
| 4 |
=
| 3 |
| 4 |
（3）7.6×99，
=7.6×（100-1），
=7.6×100-7.6，
=760-7.6，
=752.4；
（4）
| 1 |
| 8 |
| 1 |
| 5 |
| 2 |
| 5 |
| 1 |
| 10 |
=
| 1 |
| 8 |
| 1 |
| 5 |
| 4 |
| 10 |
| 1 |
| 10 |
=
| 1 |
| 8 |
| 1 |
| 10 |
=
| 1 |
| 8 |
=
| 5 |
| 4 |
=1
| 1 |
| 4 |
（5）720÷15÷6，
=720÷（15×6），
=720÷90，
=8；
（6）
| 2 |
| 3 |
| 2 |
| 3 |
| 1 |
| 6 |
=
| 2 |
| 3 |
| 2 |
| 3 |
=
| 2 |
| 3 |
=4
| 2 |
| 3 |
（7）
| 2 |
| 5 |
| 3 |
| 7 |
| 4 |
| 7 |
=（
| 2 |
| 5 |
| 3 |
| 5 |
| 3 |
| 7 |
| 4 |
| 7 |
=1+1，
=2；
（8）（6+
| 3 |
| 8 |
=（6+
| 3 |
| 8 |
| 1 |
| 3 |
=6×
| 1 |
| 3 |
| 3 |
| 8 |
| 1 |
| 3 |
=2+
| 1 |
| 8 |
=2
| 1 |
| 8 |