The value of 62 tens is 620. it is 620 because if you writes tens as a number it will be 10. So 64*10=640. An easier way to multiply 64 by 10 to get 640 is to first multiply 64*1 that the 1 came from the 10.So 64*1=64. Then you add a zero the 64 to make it into 640. Also, the zero cam from the 10. That is called mental math.