Problem No. 19. Divisibility

For which values of \(n\), is \(2n+5\) divisible by 7? And for which values, is it divisible by 30?

Student tip

Check with the reminders of \(n\) when dividing by 7. A number is divisible by 30, if it is divisible by 2, 3 and 5.

Problem No. 12. Sum of squares

Find all representations of the number 730 as a sum of two squares? And as a sum of three squares?

Teacher tip

Suitable for implementing the elimination and reminder methods while practicing the square numbers up to \(30^2\).

Problem No. 8. Seven 7s

How can you make 30, using seven 7s and the basic math operations (brackets are allowed)? What is the smallest number of 7s you can use, to make 30?

Parent tip

Have fun with your kids by exploring and calculating different number sentences. Do not forget that the brackets can help a lot.