Complex sentence: The design solved a few outstanding known problems in numerical computing and numerical software: rounding error problems were eliminated for 64-bit operands, and numerical mode conversions were solved for all 64-bit numbers.
Split into simpler sentences: The design solved a few outstanding known problems in numerical computing and numerical software. Rounding error problems were eliminated for 64-bit operands, and numerical mode conversions were solved for all 64-bit numbers.