The process formula should also be used to calculate the formula and the process

Area of Europe = 9 million x 10 9 = 10 million square kilometers.

Area of North America = 9 million 5 12 = 21.6 million square kilometers.

Area of Asia = 21.6 million 6 11 = 39.6 million square kilometers.

Antarctica area = 21.6 million 12 7 = 12.6 million square kilometers.

Area of South America = 21.6 million x 3 4 = 16.2 million square kilometers.

Area of Africa = 1620 3 5 = 27 million square kilometers.

Fill in: 4400 3000 2400 1800 1400 1000 900

Area of Europe = Area of Oceania 10 9 = 900 10 9 = 10 million square kilometers.

Area of North America = Area of Europe 5 12 = 1000 5 12 = 24 million square kilometers.

Area of Asia = Area of North America 6 11 = 2400 6 11 = 44 million square kilometers.

Area of Antarctica = Area of North America 12 7 = 2400 12 7 = 14 million square kilometers.

Area of South America = Area of North America 3 4 = 2400 3 4 = 18 million square kilometers.

Area of Africa = Area of South America 3 5 = 1800 3 5 = 30 million square kilometers.

I've written the answer.

(1) Calculate the number of students in each grade; 88 + 4 = 92 in first grade, 95 + 4 = 99 in second grade, 106 + 4 = 110 in third grade, 114 + 6 = 120 in fourth grade, 130 + 6 = 136 in fifth grade, 124 + 6 = 130 in sixth grade

The number of visitors in each batch cannot exceed 230, 92+136=228 for 1st and 5th grades, 99+130=229 for 2nd and 6th grades, 110+120=230 for 3rd and 4th grades

2) 1, all with van 230 10 * 40 = 920 yuan 3 buses 5 * 120 + 3 * 40 = 720

The natural numbers are. Those who meet the conditions of 400 440 have four rental stoves. They are +5=437. After careful calculation, only 423 and 432 were eligible.

There are answers to all questions ( Pick and reach.

400 divided by four equals 100 100 times 54 equals 5400