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Difficulty: Extreme A teacher wrote a whole number on the whiteboard and asked her students to say what numbers it could divide by. The 1st student said, “the number is divisible by 1.” The 2nd student said, “the number is divisible by 2.” The 3rd student said, “the number is divisible by 3.” And this […]

Difficulty: Tricky Fernando has 3 water-tight containers that measure 3 cups, 9 cups, and 20 cups (for brevity, these are referred to as C3, C9, and C20, respectively). The containers have no markings to indicate other volumes, so there’s no way to know when a container is, say, half full. The containers have nice spouts, […]

Difficulty: Fun There are 50 total dogs signed up for a dog show. There are 30 more small dogs than large dogs. How many small dogs have signed up to compete in the show?

Difficulty: Fun Mariana the astronaut weighs 51 kilograms on Earth and 8.5 kilograms on the Moon. Mariana is training Javier to go to the Moon. If he weighs 78 kilograms on Earth, how much will he weigh on the Moon?

Difficulty: Tricky You’ve just joined a new Scouts group! You meet 4 other new people, and everyone is going around giving handshakes. If everyone shakes hands with everyone else exactly once, how many handshakes will there be in total? (Remember you can’t shake hands with yourself.)

A sea sponge gets attacked by a shark and is ripped into 100 pieces. Luckily, sea sponges can join back together after they’ve been broken apart. Some pieces form into groups of 7, and the rest form into groups of 29. In the end, there are no pieces left. How many sponges do we end […]

Difficulty: Tricky Consider the following sequence of numbers. What number comes next? 1, 1, 2, 3, 5, 8, 13…

Lisa had a difficult time falling asleep on Wednesday night, so she began counting sheep. How many sheep did she count?

What is the area of the orange star in the centre? The blue circles each have an area of 3 square centimetres, and the big square has sides that are 4 centimetres long.

Jing is taking her submarine to the bottom of an ocean trench. The first day she goes half the distance to the bottom of the trench.