IGCSE Chapter 1 Revision

True or False.

1 is a prime number.

• True

• False

Tags

CCSS.4.OA.B.4

Which list has only prime numbers?

• 2, 3, 4, 5
• 1, 5, 7, 9
• 2, 3, 5, 7
• 2, 4, 6, 8

Tags

CCSS.4.OA.B.4

Find the prime factorization of 72

• 2³ x 3²

• 2 x 3² x 4

• 2⁴ x 3³

• 2² x 6²

What is the prime factorization of 192 ? 

• 3 ⋅ 6²
• 2⁶ ⋅ 3
• 2⁸ ⋅ 3
•  3 ⋅ 8² 

What is the sum of the three largest prime numbers smaller than 30?

• 67

• 41

• 71

• 59

What is the product of the three smallest prime numbers?

• 2

• 6

• 105

• 30

Hints: xy=-36, x - y = 13. Find two possible pairs (x,y).

• x = 4, y = -9 or x = 9, y = -4

• x = 5, y = -8 or x = 8, y = -5

• x = 7, y = --6 or x = 6, y = -7

• x = -4, y = 9 or x = -9, y = 4

Find a positive integer that is one fifteenth of its own square.