Is 1, 2, 19 or 21 closest to 12/13 + 7/9? [pdf]

I'd say there's a big difference between someone choosing one of the first two answers versus the last two.

Much worse is the example showing their inability to eliminate answers when multiplying decimals.

In 1978, a US-based study posed this question to 20,000 8th graders. Just 24% selected the correct answer. This is basically equivalent a random guess. In 2014, the same question was posed to 48 suburban US students. Only 27% selected the correct answer.

The answer is so obvious that it isn’t even worth testing or commening on.<p>Did you guess correct one, btw?