It Works Both Ways: Transfer Difficulties between Manipulatives and Written Subtraction Solutions
Figure 1
The Digi-Block system, demonstrating the subtraction problem, “31–22.” In (a), three blocks of ten on the left side of the counter and a single small block on the right side represent the number “31,” which has been recorded below the blocks. In (b), a block of tens has been removed (“borrowed”) from the tens position and opened; the ten small blocks inside the borrowed block of ten have been placed to the right side of the counter. The remaining blocks represent the subtrahend (22), which has been recorded beneath the minuend. In (c), two blocks of ten and two single blocks have been removed. The number of remaining blocks (09) has been recorded.
