how to see number of great grandkids someone has

my great grandmother had 45 grandchildren, but I am unsure how many great grandkids she had.. they are all entered here, but it would be too hard to go to each of the 45 grandkid's pages and then have to add them all (it is over 85)...is there an easier way to see it?  the most info I can see on my great grandma's profile page is siblings and children.. thanks.