The figure in purple must equal 4. This is because the number is multiplied by itself and equals 16; the only positive number that can be squared and equal 16 is 4.
This makes the vampire equal to 3. This is because 4 multiplied by the vampire and again by the vampire is 36; this means the vampire multiplied by itself must be 9. This makes the vampire equal to 3.
The mummy must be equal to 6. This is because the purple figure multiplied by the vampire multiplied by ;the mummy is 72; this means 4*3*(mummy) is 72; 12(mummy) = 72; the mummy must be 6.
