2. Check the correct option.

(1) A Xinhua dictionary has 100 pages (∩) 1430 pages () and 9874 pages ().

There are 45 students (∩)800 students (∩)3 100 students (∩) in the experimental primary school.

(2) If Xinhua Dictionary has 1000 words per page, then this dictionary has about (10) million words.

(3) The experimental primary school has an average of 45 students in each class, and there are about (18) classes in this primary school.

I think the above problem is an estimation problem, as long as it is basically practical.

3. (This question is unnecessary)

solve problems

(1) Two trains A and B leave from two places at the same time and meet at 4 o'clock. It is known that car A travels 65KM per hour and car B travels 55KM per hour. Find out how many meters apart the two places are. (65+55)*4=480 km

(2) Shirt 420 yuan, pants 2 10 yuan, skirt 180 yuan (20% off for both).

Mother wants to buy a shirt and a pair of trousers. Is 600 yuan enough? (420+2 10)*0.8=504 yuan 504 yuan

② How much should I get back for buying these three pieces with 800 yuan? 800-(420+210+180) * 0.8 =152 yuan.