This category contains questions and answers about mathematics, chemistry, astronomy and physics.

The unit a 'cable length' is named after the length of a ship's anchor cable in the Age of Sail. What is an international cable length?

Earth's inner core is thought to consist mainly of iron and another metal. Which?

Which chemical element is by mass the third-most abundant element in the universe after hydrogen and helium?

This chemical element was discovered independently by Carl Wilhelm Scheele in 1773 and Joseph Priestley in 1774. The latter is often given priority because his work was published first. Which element?

7 x 6 = ?

8 x 6 = ?

6 x 4 = ?

9 x 9 = ?

8 x 9 = ?

6 x 5 = ?

7 x 7 = ?

9 x 8 = ?

7 x 9 = ?

6 x 7 = ?

9 x 7 = ?

9 x 3 = ?

9 x 4 = ?

8 x 8 = ?

8 x 5 = ?

3 x 7 = ?

3 x 9 = ?

8 x 7 = ?

4 x 4 = ?

5 x 6 = ?

5 x 7 = ?

5 x 8 = ?

5 x 9 = ?

4 x 8 = ?

9 x 2 = ?

8 x 4 = ?

9 x 6 = ?

5 x 4 = ?

6 x 6 = ?

2 x 9 = ?

7 x 8 = ?

7 x 4 = ?

4 x 9 = ?

6 x 8 = ?

4 x 3 = ?

3 x 8 = ?

5 x 3 = ?

6 x 9 = ?

3 x 4 x 3 = ?

4 x 4 x 3 = ?

5 x 4 x 7 = ?

6 x 4 x 2 = ?

7 x 3 x 5 = ?

8 x 4 x 5 = ?

7 x 5 x 6 = ?

9 x 5 x 4 = ?