Solving Grade 4 Math Problems, Exercises 1, 2, 3, 4, 5

=> Refer to Grade 4 Math Solutions here: Grade 4 Math Solutions
 

Guidance on solving Grade 4 Math Problems, Exercises (including solution methods)
 

1. Solving math problem 4 on page 99 focusing on exercise 1

Problem:
Among the numbers 7435; 4568; 66811; 2050; 2229; 35766.
a) Which numbers are divisible by 2?
b) Which numbers are divisible by 3?
c) Which numbers are divisible by 5?
d) Which numbers are divisible by 9?

Solution Method:
- Divisibility test for 2: Numbers ending with 0; 2; 4; 6; 8 are divisible by 2
- Divisibility test for 3: If the sum of the digits is divisible by 3, then the number is divisible by 3
- Divisibility test for 5: Numbers ending with 0 or 5 are divisible by 5
- Divisibility test for 9: If the sum of the digits is divisible by 9, then the number is divisible by 9.

Answers:
a) Numbers divisible by 2 are: 4568; 2050; 35766.
b) Numbers divisible by 3 are: 2229; 35766.
c) Numbers divisible by 5 are: 7435; 2050.
d) Numbers divisible by 9 are: 35766.
 

2. Solving Grade 4 Math Problem on Page 99, Exercise 2

Problem:
Among the numbers 57 234; 64 620; 5270; 77 285
a) Which numbers are divisible by 2 and 5 ?
b) Which numbers are divisible by 3 and 2 ?
c) Which numbers are divisible by 2, 3, 5, and 9 ?

Solution Method:
- Numbers divisible by both 2 and 5 have 0 as the last digit
- Numbers divisible by both 3 and 5 satisfy both of the following conditions: Their digit sum is divisible by 3, and the last digit is 0 or 5

Answers:

3. Solving Grade 4 Math Problems on Page 99, Exercise 3

Solution Method:
- Divisibility test for 3: If the sum of the digits is divisible by 3, then the number is divisible by 3
- Divisibility test for 9: If the sum of the digits is divisible by 9, then the number is divisible by 9
- Divisibility test for both 3 and 5: If the sum of the digits is divisible by 3 and the last digit of the number is 0 or 5
- Divisibility test for both 2 and 3: If the sum of the digits is divisible by 3 and the last digit of the number is 0, 2, 4, 6, or 8

Answers:
a) Fill in the blanks with the digits 2, 5, 8: 528; 558; 588.
b) Fill in the blanks with the digits 0, 9: 603; 693.
c) Fill in the blanks with the digit 0: 240.

4. Solving Grade 4 Math Problems on Page 99, Exercise 4

Problem:
Calculate the value of each expression then determine which of the numbers 2 and 5 it is divisible by:
a) 2253 + 4315 - 173                              b) 6438 - 2325 x 2
c) 480 - 120 : 4                                        d) 63 + 24 x 3

Solution Method:
* Perform operations in the following order:
- For question a): Expression involves addition and subtraction, so perform operations from left to right
- For question b): Expression involves multiplication and subtraction, so perform multiplication first, then subtraction
- For question c): Expression involves division and subtraction, so perform division first, then subtraction
- For question d): Expression involves multiplication and addition, so perform multiplication first, then addition
* Divisibility signs:
- Number divisible by 2 has digits ending with 0; 2; 4; 6; 8
- Number divisible by 5 has digits ending with 0 or 5.

5. Solve problem 4 on page 99 to focus on exercise 5.

Solution method:
- Reading the number: Read it like natural numbers, reading from high to low digits, and after the number part, add 'square kilometers'.
- Writing the number: First, determine the class based on the letters indicating the class name; then determine the digits belonging to that class; at the end of each number, add the symbol km².

Guide to solving class 4 problem on page 99 to focus concisely

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Above are the solutions for exercises on page 99, solving the 4 practice problems on page 99 in the math exercise section for 4th grade. Students can review the Solutions for 4th Grade Math on Page 98 in the textbook previously solved or preview the Solutions for 4th Grade Math on Page 100 in the textbook to improve their understanding of 4th-grade Math.