This resource include 48 pages of addition and subtraction problems in increasing complexity: from addition and subtraction problems within 20, without regrouping or borrowing (composing a ten or decomposing a ten), to addition and subtraction of numbers within 10,000 that include regrouping/composing/bundling or borrowing/decomposing/unbundling 10s,100s, or 1,000s. There are 6 problems on each page. The problems are written in the horizontal form, thus students are encouraged to copy the proble