Divide the given expression into 5 sets of 2 numbers as follows:
2+6+10+14+18+22+26+30+34+38=(2+38)+(6+34)+(10+30)+(14+26)+(18+22)
Combinations of 2 numbers in each set shown above are just for easier calculations. Any combination of 2 different given numbers will be OK.
Thus, {(2+38)+(6+34)+(10+30)+(14+26)+(18+22)}/2=(40*5)/2=(40/2)*5=20*5=100
Therfore, if the fraction-form is allowed in this problem, one of the answers with additional five digits of 2 will be as follows: (2+38)/2+(6+34)/2+(10+30)/2+(14+26)/2+(18+22)/2 (=100)
As mentioned above, for example, (2+6)/2+(10+14)/2+(18+22)/2+(26+30)/2+(34+38)/2 (=4+12+20+28+36=100) will be one of the answers as well.