Singapore Math is a cohesive, deep, and focused mathematics curriculum, for Kindergarten through Seventh Grade, with the goal of developing algebraic thinking. Algebra is a systematic approach to describing patterns and relationships and finding unknown numbers or quantities. It is a complex tool and body of knowledge, requiring strong numeracy, procedural fluency, and an ability to abstract. The explicit study of algebra begins in Eighth Grade, and the Singapore Math curriculum is the strongest available to prepare students for that challenge.
The Singapore Math curriculum presents math problems first concretely, then pictorally, and only after these steps in abstract terms that we recognize as an algorithm. For instance, students might begin with a problem of adding apples, say 2 apples and 1 apple. They might use disks, blocks, or other objects that illustrate more and less and what it is to regroup. The next step would have them represent the problem on paper, using units, likes 1s, 10s, and 100s. Finally, they would encounter the problem as 2+1=3. The benefit of this multiple representation approach, which treats the algorithm as present all along but not uncovered immediately, is the principal way in which Singapore Math develops number sense.
The overall effect is that students are typically able to succeed in algebra one year before they would using many other curricula now available.