Open the numbers for easy grasp by just knowing the decimal position but also you can read directly from the numbers and checking their exponents.
1.(Jurassic) 208000000
2.(Silurian) 438000000
3.(Tertiary) 66400000
4.(Triassic) 245000000
245000000Silurian, Triassic, Jurassic and Tertiary.
245000000Silurian, Triassic, Jurassic and Tertiary. And yes you are smart! Don't sell yourself short!
245000000Silurian, Triassic, Jurassic and Tertiary. And yes you are smart! Don't sell yourself short! All the best!