A complete 14-day Grade 3 unit covering all of CCSS 3.NBT — place value to the thousands, rounding to the nearest 10 and 100, multi-digit addition and subtraction within 1000 (with regrouping and borrowing), and multiplying one-digit numbers by multiples of 10. This is the foundation that every Grade 3+ math depends on. Built by a classroom teacher who knows that place value confusion is at the root of most computation errors, and that students need to MASTER three-digit operations before moving