Grouping numbers up to 10 means taking a small collection of objects and sorting them into equal-sized groups. It is one of the very first ways young learners meet the idea of division, long before they see a division sign written down. Instead of asking "what is 8 divided by 2?", a student is asked "if I put these 8 counters into groups of 2, how many groups do I get?" The answer, 4 groups, is exactly the same idea as \( 8 \div 2 = 4 \).
Because the numbers involved stay at 10 or below, students can actually draw, count, and move real objects (counters, blocks, fingers, drawn circles) to find the answer, rather than relying on memorized facts.