I am going to assume that the question is asking how many buttons are in each of the 8 groups.
To find out how many buttons are in each of the 8 groups, we simply need to divide the amount of groups by the total amount of buttons.
3250 / 8 = 406.25
That is unlikely the answer, since buttons are hard to divide into quarters.
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This is the more likely solution. There are 8 groups of buttons, with 3250 buttons in each group. To find the total amount of buttons, we just need to multiply the number of groups of buttons there are by the amount of buttons there are in each group.
8 * 3250 = 26000
There are 26,000 buttons total. Hope that helped =)
