NC.2.NBT.8

This standard calls for students to mentally add and subtract 10 or 100 from a given number between 100 and 900. 

• • Students should engage with concrete objects and representations to recognize that adding or subtracting 10 or 100 that only the digit in the tens place or the digit in the hundreds place changes by 1. 

  • Students should have ample opportunities to explore a 200s chart to help them make connections between adding or subtracting 100 to adding or subtracting 10. 

  • Opportunities to solve problems in which students cross hundreds (10 more than 392) should be included after students have become comfortable adding and subtracting within the same hundred.