In order to save materials and not waste, the side length of a square must be the common divisor of length and width, and the greatest common divisor of 35 and 50 is 5, so only a square with a side length of 5CM can be selected.
Two methods:
50÷5= 10
35÷5=7
10×7=70 (block)
The second type:
(50×35)÷(5×5)
= 1750÷25
=70 (block)
Are you satisfied? How about adding 30 points?