How many four-digit numbers with a sum of their digits equal to 2 are there?

Which symbol makes the steam in true 0.7 > 0.77

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

Noor brought 21 sheets of stickers. she gave 1/3 of a sheet to each of the 45 students at recess. she wants to give teachers 1 1/2 sheets each.