Concentration time

I am curious as to what is the ideal time for toddler or young child to learn something?
For example doing HOP workbook, followed by flash cards, is 20 minutes per subject too long for a 34 month old? Is there a recommended guideline anywhere? thanks.

it depends to ur child’s interest

20 minutes is fine if your child shows interest on studying the subject.
if you are starting to teach newly then you you need to know whether child keep interest and do concentrate on the subject well. and dont try to teach 20 min or 10 min with low concentration
just try to make teaching as something enjoying and learning fun

Actual concentration is actually quite low at that age according to guidelines, but if your child is interested then they will concentrate far longer. Do something as long as it is fun and they are stimulated - losing concentration is a sign you should put it away. My daughter is nearly 4 and some activities she can do for almost two hours, others need to be 5 minutes or less.

when we have “school time” in the evenings, we do a variety of subject and I would guess that each lasts from 10-20 minutes? probably an average of 15. HOP, math (which is way shorter than reading, sometimes even just 5 minutes to quickly do one addition & one subtraction with no manipulatives) cutting/coloring/gluing, sometimes we do early bird math workbook or unifix cubes, mouse control/computer games, Spanish vocabulary, geography but not as much as we should. Sometimes school takes 30 minutes if we only do a couple subjects, sometimes longer than an hour, but usually around 40-80 minutes if I had to put a number on it. i don’t know what the average or recommended is, we just do it as long as we’re having fun and interested.

Thanks for all the replies.
I am also curios to know whether concentration and perseverance are something that can be trained up, like stamina?
maybe a more proper schedule to start when she goes to kindergarten at 3?

DD’s stamina has increased for sure since we first started having “school time” in the evenings. We used to do it during DS’s morning nap but when he dropped his nap we had to adjust, and she was initially a bit crankier in the evenings but she grew accostomed to it. Now she asks for school because it’s fun and she gets to stay up a bit later. lol

But yes, her ability to focus has naturally increased over time for SURE, no doubt. A skill, like anything else, it just naturally developed.