(1) positive integer and (negative integer) and (zero) are called integers, and (zero) and (positive integer) are called natural numbers. The number of integers is (infinite), and there is neither maximum nor minimum.

(2) The numbers we have learned are divided into (positive), (negative) and (zero) according to their symbols.

(3) Four fifths means dividing a whole (on average) into (5) parts, which means that such (4) parts are a (score).

(4) Decimals with zero integer parts are called (with decimals), and decimals with non-zero integer parts are called (pure decimals).

(5)6.373737。 . . . . . Is a (cyclic decimal), which can be simply expressed as (6.37 (there is a point on 3 and 7)).

(6) There is (150) 0.0 1 in1.After simplification, there is 36,000.01yes (3.6).

(7) The decimal consisting of six thousands, three tens and three tenths is (6030.3).

(8) The general methods for finding the divisor are (rounding method), (rounding method) and (one-in-one method), and the most commonly used method is (rounding method).

Column calculation

The sum of (1) five is 3.24 times the product of two 0. 1 What is the result?

Answer: (5x3.24) x (0.1x 0.1) =16.2x0.01= 0.162.

application problem

(1) Xiao Pang read a book. He read 40 pages, and the remaining five pages were less than three times what he read. How many pages are there in this book?

Answer: 40x3-5+40 = 155 (page)

A: This book has 155 pages.

(2) the canteen to buy a batch of rice, eat 50 kg a day, can eat for 20 days; If you eat 40 kilograms a day, how many days can you eat this batch of rice?

Answer: 50x20÷40 = 25 (days)

A: Eat 40 kilograms a day, and this batch of rice can be eaten for 25 days.

(3) There is a pile of 580 tons of coal to go. 60 tons per day for the first five days and 70 tons per day for the rest of the day. How many days will it take?

Answer: (580-60x5)÷70 = 4 (days)

A: It will take four days to complete the shipment.

(4) There are 690 peach trees and pear trees in the orchard, which is four times less than that of pear trees, namely 10. How many pear trees are there in the orchard?

Solution: (690+ 10)÷4 = 175 (tree)

There are 175 pear trees in the orchard.

(5) Li Shifu wants to process a batch of parts, and it plans to process 25 parts a day, but it actually processes 5 more parts a day than planned, so it actually takes only 5 days to complete the task. Li Shifu originally planned to complete these tasks in a few days. Solution: (25+5)x5÷25 = 6 (days)

A: Li Shifu originally planned to complete these tasks within six days.