MYTS 2017 - Grade 4 - Round 2

Among the natural numbers from 1 to 203 inclusive, Linh lists those divisible by 3 but not by 2, obtaining L numbers. Khánh lists those divisible by 2 but not by 3, obtaining K numbers. Find K − L.

The diagram is a pyramid of 10 squares. Write a natural number in each square so that, except in the bottom row, each number is the sum of the two numbers immediately below it. The filled diagram gives an example. Mr Thuận wants a filling with exactly four even numbers. Show one such filling.

Cut the shape with the bold boundary into two congruent shapes, cutting only along the square grid lines. Two shapes are congruent if one can be placed exactly over the other.

There are three cards labelled 1, one labelled 5, one labelled 7, and one labelled 8. How many six-digit natural numbers can be formed by placing all six cards in a row?

A rectangle is assembled from 16 congruent smaller rectangles as shown. Each small rectangle has perimeter 40 cm. Find the perimeter of the large rectangle, in centimetres.

A forest contains 6 red, 3 blue, and 11 yellow chameleons. Whenever two differently coloured chameleons meet, both change to the third colour. Can all 20 chameleons become the same colour? Why?