Buzz
=> Continue following further 4th-grade Math problem-solving here: 4th-grade math problems solutions
Guidance on solving exercises from page 61 of Math 4, including solution methods
1. Solving exercise 1 on page 61 of Math textbook for 4th grade
Problem:
Calculate in 2 ways (following the example):
Example: 2 x 5 x 4 = ?
Method 1: 2 x 5 x 4 = (2 x 5) x 4 = 10 x 4 = 40.
Method 2: 2 x 5 x 4 = 2 x (5 x 4) = 2 x 20 = 40.
a) 4 x 5 x 3 b) 5 x 2 x 7
3 x 5 x 6 3 x 4 x 5
Solution method:
Applying the associative property of multiplication, we have: (a x b) x c = a x (b x c)
=> From these principles, students calculate the expression in 2 ways.
Answer:
a) 4 x 5 x 3 = ? b) 5 x 2 x 7 = ?
Method 1: 4 x 5 x 3 = (4 x 5) x 3 = 20 x 3 = 60. Cách 1: 5 x 2 x 7 = (5 x 2) x 7 = 10 x 7 = 70.
Method 2: 4 x 5 x 3 = 4 x (5 x 3 ) = 4 x 15 = 60. Cách 2: 5 x 2 x 7 = 5 x (2 x 7) = 5 x 14 = 70.
+) 3 x 5 x 6 = ? +) 3 x 4 x 5 = ?
Method 1: 3 x 5 x 6 = (3 x 5) x 6 = 15 x 6 = 90. Cách 1: 3 x 4 x 5 = (3 x 4) x 5 = 12 x 5 = 60.
Method 2: 3 x 5 x 6 = 3 x (5 x 6) = 3 x 30 = 90. Cách 2: 3 x 4 x 5 = 3 x (4 x 5) = 3 x 20 = 60.
2. Solving exercise 2 on page 61 of Math textbook for 4th grade
Problem:
Calculate in the most convenient way:
a) 13 x 5 x 2 b) 2 x 26 x 5
5 x 2 x 34 5 x 9 x 3 x 2
Solution method:
Students apply the associative property of multiplication: (a x b) x c = a x (b x c) to group two numbers so that when multiplied together, they become a multiple of 10, and then multiply by the remaining number.
Answer:
a) 13 x 5 x 2 = 13 x (5 x 2) = 13 x 10 = 130.
5 x 2 x 34 = (5 x 2) x 34 = 10 x 34 = 340.
b) 2 x 26 x 5 = 26 x (2 x 5) = 26 x 10 = 260.
5 x 9 x 3 x 2 = (9 x 3) x (5 x 2) = 27 x 10 = 270.
3. Solving problem 3 on page 61 of Math textbook for 4th grade
Problem:
There are 8 classrooms, each with 15 sets of desks and chairs, with 2 students sitting in each set. How many students are currently studying?
Solution method:
- The problem states: 8 classrooms, 15 sets of desks and chairs, and 2 students sitting in each set
- Problem requirement: Calculate the total number of students currently studying
- Solution approach:
+ Calculate the number of students in each classroom by multiplying the number of sets of desks and chairs by the number of students sitting
+ Calculate the total number of students currently studying by multiplying the number of students in each classroom by the number of classrooms.
Answer:
The number of students in each classroom is:
2 x 15 = 30 (students)
The total number of students currently studying is:
30 x 8 = 240 (students)
Final answer: 240 students.
Concise Guide to Solving Exercise on page 61 Math 4
Solving exercises on pages 59, 60 Math Textbook for 4th grade from the previous session was just a part of multiplication. The associative property of multiplication is demonstrated when multiplying a product of two numbers by a third number, we can multiply the first number by the product of the second and third numbers. Along with that are examples guiding how to solve problems involving the associative property of multiplication that you can refer to for quick and easy learning. Additionally, students can also refer to detailed solution systems and guides to solve exercises on page 61 Math 4 more quickly and effectively.
In addition to the lesson above, students also need to refer to the content of Solving Math 4 on page 29 about charts to understand more about topics such as chart drawing, interpreting information from charts to be able to apply them to other contents in the future.
After this lesson, we will together explore how to solve exercises on page 62 Math Textbook for 4th grade. I invite you all to follow along and understand the details to apply to your study needs easily and achieve higher results.
