(360+8+8× 2+8× 3+8× 4+8× 5) ÷ 6 = 480 ÷ 6 = 80 (person)

2. The10 layer is arithmetic progression with a tolerance of 8, and the outermost layer is 16+8× 9 = 88 (tree).

(16+88) × 10 ÷ 2 = 520 (tree)

520× 60 = 3 1200 (g) = 3 1.2 (kg)

It seems that there are too few peaches per tree!

3.0. 1 to 10 * * 100 is divided into 50 groups, each group is 10-9.9 = 0. 1, 0. 1× 50 = 5.

10-9.9+9.8-9.7+9.6-9.5+……+0.4-0.3+0.2-0. 1

=( 10-9.9)+(9.8-9.7)+(9.6-9.5)+……+(0.4-0.3)+(0.2-0. 1)

=0. 1×50=5

4. The number of100 is divided into 25 groups, each group is 10+9.9-9.8-9.7 = 0.4, 0.4× 25 = 10.

10+9.9-9.8-9.7+9.6+9.5-9.4-9.3+9.2+9. 1-9-8.9+……+0.8+0.7-0.6-0.5+0.4+0.3-0.2-0. 1

=( 10+9.9-9.8-9.7)+(9.6+9.5-9.4-9.3)+…+(0.8+0.7-0.6-0.5)+(0.4+0.3-0.2-0. 1)

=0.4×25

= 10