7+2 = 9 7x 1/9 = 7/9 2x 1/9 = 2/9

3.6X2/9=0.8 hectares 3.6X7/9=2.8 hectares

Answer; Rice planting area accounts for 7/9 of the total area, and vegetable planting area accounts for 2/9 of the total area. Planting 0.8 hectares of rice and 2.8 hectares of vegetables. 2.

2+3+ 1=6

2x 1/6 = 1/3 3x 1/6 = 1/2 1x 1/6 = 1/6

180X 1/3=60 (degrees) 180X 1/2=90 (degrees) 180X 1/6=30 (degrees).

Answer; The degrees of the three internal angles of a triangle are 60 degrees, 90 degrees and 30 degrees respectively.

Two. 1.

15+ 16=3 1

15x 1/3 1 = 15/3 1 1/3 1 = 16/3 1

1240x15/31= 600 (yuan)

Answer; The fifth grade was donated to 600 yuan, and the sixth grade was donated to 640 yuan.

2.

1+3+4=8

1x 1/8 = 1/8 3x 1/8 = 3/8 4x 1/8 = 1/2

480X 1/8=60 (ton) 480X3/8= 180 (ton) 480X 1/2=240 (ton)

Answer; 60 tons of cement, 0/80 tons of sand/kloc and 240 tons of stone.

3.

20+24+26=70 (person)

20x 1/70 = 1/7 24x 1/70 = 12/35 26x 1/70 = 13/35

140X 1/7=40 (block) 140X 12/35=48 (block) 140X 13/35=52 (block).

Answer; The big class is divided into 40 blocks, the middle class is divided into 48 blocks and the small class is divided into 52 blocks.