It's worded in such a way as to be meaningless - half of what? The original number of Russian soldiers, the original number plus Wagner and other extra troops, the current number deployed with/without mercenaries? Plus Russia's numbers don't look like US numbers, don't quite look like Ukraines numbers.
That said heres the first source I found:
Russia’s military casualties, the officials said, are approaching 300,000. The number includes as many as 120,000 deaths and 170,000 to 180,000 injured troops. The Russian numbers dwarf the Ukrainian figures, which the officials put at close to 70,000 killed and 100,000 to 120,000 wounded.
...
Russia has almost triple that number, with 1,330,000 active-duty, reserve and paramilitary troops — most of the latter from the Wagner Group.
Those numbers refer to the current number of deployed and undeployed Russian soldiers plus mercenaries, which is clearly not the numbers the ad is using.
To be clear, I fully support Ukraine and fully support the US guaranteeing missile manufacturers that we will buy new missiles even if the war ends tomorrow to incentivise greater production. I just think the ad played with the numbers until they said what we want them to say.