create a dice. With bolean operations.
. Create a Cube.
Create a dice-1.jpg

Use the filleting tool. Press the + key, and hit return.
Create a dice-2.jpg

Create a sphere, rotate it.
Create a dice-3.jpg

Create a dice-4.jpg

Your sphere must be at the right scale, and at the right place. Use the proportional scale and move tools.
Create a dice-5.jpg

Select the sphere, choose the punch tool, click on the Cube. Use the + and - Keys todo display successively the diferent combinations between the two intersected objects. Press.
Return when wanted shape is shown.
Create a dice-6.jpg