It can be seen that the unit number is 7.9.3. 1 In other words, the fifth power unit is 7.6 power unit is 9.8 power unit is 3. Then the ninth power unit is 1.
Divide 100 by 4. Divided by 25, there is no remainder. It means that the power of 100 has been cycled 25 times. The last digit ends in 1