2. Testing is also the greatest common divisor. The greatest common divisor of 36 and 24 is 12, that is, the largest square side length is 12 cm, which can be cut into (36/ 12)*(24/ 12)=6 blocks.
3. This test is the least common multiple, that is, the least common multiple of 30 and 45 is 90, and then you can know that the third root sign is the next one you don't understand as long as 90/30=3.
4. The test is the least common multiple, and the least common multiple of 30 and 20 is 60, that is, (60/30)*(60/20)=6 blocks.