Addition and Subtraction to 10,000

Addition and subtraction to 10,000 extend the strategies from Grade 3 to four-digit numbers. Decompose 6,847 + 2,365 into thousands, hundreds, tens, and ones, add each independently, then recombine: 8,000 + 1,100 + 11 + 12 = 9,212 (with regrouping). The same place-value logic applies; the numbers are simply larger. Estimation becomes more critical as numbers grow larger, because errors are harder to spot without a predicted target.