1_000_000_000
1.1_00_01
1e1_0
1e+1_0
1e-1_0
1.1e10_0
1.1e+10_0
1.1e-10_0
12_34_56
1_22_333
1_2.3_4
1_2.3_4e5_6
1_2.3_4e+5_6
1_2.3_4e-5_6