@ JackPedigo
1 Both are mathematically incorrect, "is" is grammatically correct.
2 12 presuming we are still talking about the stamps
3 Bread or bread like products
4 Infant cows drink milk adult cattle tend to drink water

@Fernapple

1 Dogs (Latin cannis)
2 116 year 1337 to 1453
3 Until they die
4 Always a reptile sometimes a quadruped but often a nullaped (snakes, sidewinders, etc)

I prefer the question:
"What is the grammatically correct wording, the yolk of the egg is white, or the yolk of the egg are white?"

What animals are the Canary Islands named after ?

How long did the Hundred Years War last ?

Under traditional Jewish law, if there is a train crash, how long do you have before you must bury the survivors ?

Is a lizard a reptile or a quadruped ?

9 and 7 is 16
12
Bread, muffin
Water