These kids don’t understand decimals. Many of them, even if they are college graduates, they don’t understand decimals. If you ask them which is smaller, 0.1 or 0.09 they can’t tell you.
My sister taught math for 45 years to middle school and high school students. She had lots of kids graduating from high school who were unable to divide 1/2 by 2. She would patiently explain about taking a half of an apple and cutting it in two, then ask what you had. The kids would get it using examples like that. But move into the abstract (1/2 divided by 2) and they were totally lost.