Berlindes / Marbles

O Ricardo deu metade dos seus berlindes ao seu amigo Miguel, mas quando chegou a casa, a sua mãe tinha um saco com 25 berlindes para lhe oferecer. No dia seguinte, levou todos os seus berlindes para a escola e quando lá chegou reparou que, pelo caminho, tinha perdido 9 berlindes, uma vez que no seu saco já só tinha 18. Quantos berlindes tinha o Ricardo no início?



Ricardo gave half of his marbles to his friend Miguel, but when he got home, his mother had a bag with 25 marbles to offer him. On the following day, he took all his marbles to school and when he arrived he noticed that, along the way, he had lost 9 marbles, as in his bag he only had 18. How many marbles had Ricardo at the beginning?

The Cube Painter

Carlos built a large cube with 64 small cubes of the same size. Then he decided to paint with gray five faces of the large cube, as we can see in the picture. How many small cubes are there with three gray faces?

O Carlos construíu um cubo grande a partir de 64 cubos pequenos do mesmo tamanho. Depois, decidiu pintar a cinzento 5 faces do cubo grande, como podemos ver na figura. Quantos cubos pequenos é que ficaram com 3 faces cinzentas?

Adapted by Monte Flor Teacher Rui Lima from Canguru Matemático - Prova Escolar 2010