Divisibility Rules and Prime Numbers

Teacher Diane introduces whole numbers and explores various divisibility rules, including those for 5, 9, 3, 6, and 9. The lesson includes problem-solving exercises involving arranging desks, distributing mangoes, and understanding odd numbers. Concepts like the greatest common divisor and least common multiple are applied to practical problems, such as synchronizing clocks. The video concludes with identifying prime numbers between 70 and 80.

What is a whole number?

• A number without fractions

• A number with fractions

• A decimal number

• A negative number

Which of the following numbers is divisible by 5?

• 67

• 45

• 23

• 89

How do you determine if a number is divisible by 9?

• Divide by 3 and check the remainder

• Check if the number is even

• Add the digits and see if the sum is divisible by 9

• Check if the last digit is 9

What must be true for a number to be divisible by 6?

• It must be divisible by 2 and 3

• It must be divisible by 9

• It must be divisible by 5

• It must be a prime number

If a classroom has 27 desks, how many rows can be made with no desks left over?

• 12

• 9

• 3

• 15

What is the divisibility rule for 4?

• The number is even

• The sum of digits is divisible by 4

• The last two digits form a number divisible by 4

• The last digit is 4

How many baskets can be made from 210 mangoes if each basket must have the same number of mangoes?

• 21

• 15

• 20

• 10

If a group of students collected 16,490 pesos, how many students could there be if each paid the same amount?

• 15

• 16

• 17

• 18

If n is an odd number, which of the following must also be odd?

• n + 2

• n + 1

• n * 2

• n/2

What is the greatest common divisor of 54, 36, and 24?

• 6

• 3

• 12

• 9