Question

1. （1/4+2）×1又1/3-（2/25÷0.4+1/5×3.8）

2.
2又4/9÷[（8又5/12-6.75）÷22又1/2+4又16/21×7/12]
3.
[（2.75×5/7+2又3/4÷3又1/2）×1又1/11]÷0.375
4.
2² 4² 6² 8²
━━━━━+━━━━+━━━━+━━━━
1×3 3×5 5×7 7×9

Answer 1

1. （1/4+2）×1又1/3-（2/25÷0.4+1/5×3.8）
=6/4×4/3-（2/25÷2/5+0.76）

=2-（1/5+0.76）
=2-0.96
=1.04

2.
2又4/9÷[（8又5/12-6.75）÷22又1/2+4又16/21×7/12]
=2又4/9÷[5/3÷45/2+25/9]
=2又4/9÷[2/27+25/9]
=22/9÷77/27
=6/7

3.
[（2.75×5/7+2又3/4÷3又1/2）×1又1/11]÷0.375
=[（2.75×5/7+2.75×2/7）×12/11]÷3/8
=[2.75×（5/7+2/7）×12/11]÷3/8
=[11/4×12/11]÷3/8
=3÷3/8
=8

4.
2² 4² 6² 8²
━━━━━+━━━━+━━━━
1×3 3×5 5×7 7×9
1 1 1 1
=1+━━━━━+1+━━━━+1+━━━━+1+━━━━
1×3 3×5 5×7 7×9
=4+1/2×（1-1/3+1/3-1/5+1/5-1/7+1/7-1/9）
=4+1/2×（1-1/9）
=4+1/2×8/9
=4+4/9
=4又4/9

Answer 2

你发图片吧