Reviewing numbers within 1000

### 1.1. Knowledge to remember

– Can read and write natural numbers from left to right.

– Compare numbers up to 1000.

Know the structure of three-digit numbers.

– Add, subtract (don’t remember or remember) within 1000

– Determine the number before and after the number of a number.

– Apply calculations to solve word problems.

### 1.2. Types of Maths

**Type 1: Read and write numbers**

– Read numbers in order of rows from left to right.

– From reading numbers, I write the digits corresponding to the rows and then combine them to get a three-digit number.

**Form 2: Find the number before and after the number of a number**

– The preceding number of A is a number whose value is one unit less than A

– The next number of A is a number that is one unit larger than A.

**Form 3: Compare numbers**

Numbers with fewer digits have a smaller value.

– Two numbers have three digits, you compare the rows from left to right.

**Form 4: Order of numbers**

– Compare numbers.

– Sort the numbers in ascending or descending order within 1000.

### 1.3. Solve textbook exercises page 168

**Lesson 1**

Write the numbers:

Nine hundred and fifteen Two hundred and fifty

Six hundred and ninety-five Three hundred and seventy-one

Seven hundred fourteen Nine hundred

Five hundred and twenty-four One hundred and ninety-nine

One hundred and one Five hundred and fifty-five

__Solution method__

Determine the values of the hundreds, tens, and units, and then write the appropriate 3-digit number.

__Solution guide__

The numbers are written as follows:

915 250

690 371

714 900

524 199

101 555

**Lesson 2**

Number ?

__Solution method__

Count up the numbers and fill in the missing numbers in the blanks.

__Solution guide__

**lesson 3**

Fill in the dotted space with the appropriate hundred round numbers:

100;…; 300;…;…;…;700;…;…;1000

__Solution method__

Count by 100 units, starting at 100 and then fill in the missing number in the blank.

__Solution guide__

100; **200**; 300; **400**; **500**; **600**; 700; **800**; **900**; 1000.

**Lesson 4**

Enter the sign >; < or = is appropriate for the dot:

372…299 631 …640

465…700 909…902 + 7

534….500 + 34 708…807

__Solution method__

– Calculate the value of the calculated sides.

– Compare pairs of digits in the same row in order from left to right.

__Solution guide__

372 > 299 631 < 640

465 < 700 909 = 902 + 7

534 = 500 + 34 708 < 807

**Lesson 5**

a) Write the smallest three-digit number.

b) Write the largest three-digit number.

c) Write the next number of 999.

__Solution method__

– The smallest three-digit number: Select the digits of hundreds, tens, and units by numbers with values as small as 0; first.

– Largest three-digit number: Choose the number with digits equal to 9.

– The next number of a is one unit larger than a.

__Solution guide__

a) The smallest three-digit number is 100.

b) The largest three-digit number is 999.

c) The next number of 999 is 1000.

### 1.4. Solving Textbook Exercises page 169

**Lesson 1**

Which reading does each of the following numbers represent?

__Solution method__

Read three-digit numbers from hundreds to units respectively.

Match the three-digit number with the correct pronunciation.

__Solution guide__

Match the number 307 with the reading d) Match the number 650 with the reading b)

Match the number 811 with the reading i ) Match the number 596 with the reading h)

Match the number 939 with the reading a) Match the number 745 with the reading c)

Match the number 125 with the reading g) Match the number 484 with the reading e)

**Lesson 2**

a) Write the numbers 842, 965, 477, 618, 593, 404 according to the form:

842 = 800 + 40 + 2

b) Write according to the form:

300 + 60 + 9 = 369

800 + 90 + 5 =

200 + 20 + 2 =

700 + 60 + 8 =

600 + 50 =

800 + 8 =

__Solution method__

Parse three-digit numbers into the sum of hundreds, tens, units, and vice versa.

__Solution guide__

a) 842 = 800 + 40 + 2

965 = 900 + 60 + 5

477 = 400 + 70 + 7

618 = 600 + 10 + 8

593 = 500 + 90 + 3

404 = 400 + 4

b) 300 + 60 + 9 = 369

800 + 90 + 5 = 895

200 + 20 + 2 = 222

700 + 60 + 8 = 768

600 + 50 = 650

800 + 8 = 808

**lesson 3**

Write the numbers 285, 257, 279, 297 in this order:

a) From big to small.

b) From childhood to adulthood.

__Solution method__

Compare the digits in the same row in order from left to right and then arrange them in order.

__Solution guide__

a) 297; 285; 279; 257.

b) 257; 279; 285; 297.

**Lesson 4**

Write the correct number in the dot:

a) 462; 464; 466; ….

b) 353; 355; 357; ….

c) 815; 825; 835; ….

__Solution method__

a, b: Count by 2 units, starting from the first number and then fill in the missing number in the blank.

c: Count by 10 units, starting from 815 and then fill in the missing number in the blank.

__Solution guide__

a) 462; 464; 466; 468.

b) 353; 355; 357; 359.

c) 815; 825; 835; 845.

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