https://mathdirect.com Free, open-source math app that teaches children numbers, addition, and subtraction using Direct Instruction methodology. en 2026-04-10T04:29:49.593Z https://mathdirect.com/phases/phase-1/ https://mathdirect.com/phases/phase-1/ The math journey begins here. Phase 1 introduces numbers 0-10, counting, one-to-one correspondence, and number recognition. Lessons 1-20, 14 concepts. https://mathdirect.com/phases/phase-2/ https://mathdirect.com/phases/phase-2/ Phase 2 extends counting to 20, introduces number patterns, and builds fluency with number order and comparisons. Lessons 21-40, 4 concepts. https://mathdirect.com/phases/phase-3/ https://mathdirect.com/phases/phase-3/ Phase 3 teaches addition facts to 10 systematically, starting with +1, +2, then building to all single-digit addition. Lessons 41-65, 7 concepts. https://mathdirect.com/phases/phase-4/ https://mathdirect.com/phases/phase-4/ Phase 4 introduces subtraction as 'taking away' and builds the connection between addition and subtraction. Lessons 66-85, 6 concepts. https://mathdirect.com/phases/phase-5/ https://mathdirect.com/phases/phase-5/ Phase 5 introduces place value (tens and ones), counting to 100, and addition/subtraction within 20. Lessons 86-105, 5 concepts. https://mathdirect.com/phases/phase-6/ https://mathdirect.com/phases/phase-6/ Phase 6 builds fluency with addition and subtraction facts to 20, introduces mental math strategies, and begins two-digit addition. Lessons 106-125, 4 concepts. https://mathdirect.com/phases/phase-7/ https://mathdirect.com/phases/phase-7/ Phase 7 covers two-digit addition and subtraction (with and without regrouping), word problems, and mixed practice for complete mastery. Lessons 126-150, 5 concepts.