The use of number-based versus digit-based strategies on multi-digit subtraction: 9-12-year-olds' strategy use profiles and task performance

We examined children's number-based and digit-based strategy use profiles on multi-digit subtraction problems in relation to task performance and individual (gender, grade, mathematical achievement level) and contextual (country) characteristics. 318 third- to sixth-graders solved a multi-digit subtraction strategy use task, where half of the subtraction problems had number characteristics that stimulated the number-based compensation strategy. First, latent class analyses revealed five strategy use profiles. Most children consistently relied on one strategy (either digit-based strategies or the number-based decomposition or sequential strategies) across problems. Only a minority of children demonstrated strategy variety and flexibility - more often high achievers and children from higher grades. Second, children's strategy instruction history was related to their profile of strategy use, but this relation was less straightforward than generally assumed. Finally, consistent digit-based strategy users were more accurate than consistent decomposition strategy users and varied number-based strategy users.