Complex sentence: Italian casualties amounted to 631 or 642 men killed, 2,631 wounded, 616 reported missing and a further 2,151 men suffered from frostbite during the campaign.
Split into simpler sentences: Italian casualties amounted to 631 or 642 men killed, 2,631 wounded and 616 reported missing. A further 2,151 men suffered from frostbite during the campaign.