Working systematically

There are 555 NRICH Mathematical resources connected to Working systematically
Open Boxes
problem

Open Boxes

Age
7 to 11
Challenge level
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Can you work out how many cubes were used to make this open box? What size of open box could you make if you had 112 cubes?
Build it \Up more
problem

Build it Up more

Age
7 to 11
Challenge level
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This task follows on from Build it Up and takes the ideas into three dimensions!
Build it up
problem

Build it up

Age
7 to 11
Challenge level
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Can you find all the ways to get 15 at the top of this triangle of numbers? Many opportunities to work in different ways.