Divisiblity

·      Divisibility and divisibility rules.

     A number a is divisible by b if the remainder of the division a:b is 0.  But there are some rules with which you can know if a number is divisible by another one or not without doing the division.  Here you can see a video that explains some of these  divisibility rules.

     Divisibility rules

 If you are a maths wiz, you can wach this other video  and learn some other divisibility rules that not many people know.

More divisibility rules

Now, you can test your vocabulary about divisibility rules in the following link. Pay attention to your  score!!!

Divisibility rules game

Prime numbers.

·          In the next video you can learn what a prime number is and which are the prime numbers less than 100. 

Prime numbers

If a number is not prime, we call it a composite number. For example, 6 is not prime because it has four divisors which are 1, 2, 3 and 6.

·      Guess the number.

      In this game, a student should think of  a secret number between 1 and 99 that only the teacher will know.  The other students should ask him or her, questions in order to guess that number. Examples of these questions are:

·      Is the number greather/less than….?

·      Is the number a multiple of…?

·      Is the number divisible by…?

·      The number starts with ....?

·      The number ends in…?

·      The number has  … units/tens....?

      This exercise can be done  with numbers between 100 and 200 , etc, in order to practise other numbers.

      You can also play in pairs.