# Prime and Composite Numbers in Maths Grade 7 Maths Questions With Detailed Solutions

What are prime and composite numbers in maths? Grade 7 maths questions are presented along with detailed solutions. Detailed Solutions and explanations are included.

 What are prime and composite numbers in maths? A prime number is a whole number greater than 1 that can only be evenly divided by 1 and itself. Examples: 2, 3, 5, 7, 11,... are prime numbers. If you try to divide them by numbers other than 1 or themselves, the remainder will not be zero. A composite number is a whole number greater than 1 that can be evenly divided by 1, itself and other numbers. Examples: 4, 6, 8,12..are composite numbers because: 4�2 = 2 , 4 is divisible by 1, itself and 2 6�2 = 3 , 6�3 = 2 , 6 is divisible by 1, itself, 2 and 3. 8�2 = 4 , 8�4 = 2 , 8 is divisible by 1, itself, 2 and 4. 12�2 = 6 , 12�3 = 4 , 12�4 = 3 , 12�6 = 2 , 12 is divisible by 1, itself, 2, 3, 4 and 6. Answer the following Questions on Prime and Composite Numbers. Which of the following numbers are prime? 1, 6.3, 11, 14, 13, 21, 23, 4/5, 100, 123 . Which of the following numbers are composite? 1, 8.4, 15, 13, 9/2, 24, 33. List all prime numbers between 30 and 50 inclusive. List all composite numbers between 100 and 110 inclusive. Is the sum of two prime numbers always a prime number? Is the product of two prime numbers also a prime number? Which is the largest 3 digit prime number? Which is the smallest 2 digit prime number? List all the two digit prime numbers that can be made from the digits 1, 3 and 6 (used only once each). Can you find a prime number whose least significant digit (digit on the right) is 0? Can you find a prime number whose least significant digit (digit on the right) is 5? Can you find a prime number such that the sum of all its digits is equal to 12? Detailed Solutions and explanations are included.