Hihi, can explain more as my daughter dont understand why use 18 divide by 2 then minus 1?

Greetings. There are twice as many big beads as small beads. If each bracelet requires 4 big beads and 2 small beads instead of 3, there would have been 9 small beads left in total (half of the 18 big beads left). Since each bracelet uses 3 small beads, and there is one small bead left, 9-1 = 8 gives you the number of bracelets assembled. Hope this helps.

Thks!

My pleasure. I am glad your daughter can understand the solution. Guess-and-check is usually the go-to method, but I personally prefer the direct route. Regards