Evaluation for 5.3c
Materials include supports for students in connecting, creating, defining, and explaining concrete and representational models to abstract (symbolic/numeric/algorithmic) concepts, as required by the TEKS.
The Math Journeys grade 2 program provides students with supports to connect, create, define, and explain concrete and representational models to abstract concepts as required by the TEKS. In journey B3.12, “Resta por descomposición: con reagrupación,” students use base 10 blocks and visual representations to model subtraction with regrouping and connect these models to the standard written algorithm. During “Nudo: actividad 1,” students represent 75 with base 10 blocks and model the subtraction of 47 by physically exchanging four tens bars for 40 unit cubes. To help students understand why regrouping is necessary, the materials explicitly state, “Pretendemos que se dé cuenta de que tiene que quitar cuatro barras y siete cubos pequeños de la bandeja, pero que solo hay cinco cubos pequeños.” Students then create representational models by drawing bars and crosses and recording the subtraction process on the board. The lesson connects these concrete and pictorial models to abstract representations through vertical subtraction and partial differences, showing how 75 − 47 can be represented as 20 + 8 = 28. To help students define and explain the relationship between the models and the numerical procedure, the materials further clarify that “estas cajitas recogen los resultados de restar las decenas y las unidades cuando operamos con números de dos cifras.” In activity 2, students apply the same strategy using money models with $10 and $1 bills, further connecting the regrouping concept to real-world representations. Through these supports, students connect, create, define, and explain concrete and representational models as they deepen their understanding of subtraction with regrouping.
The Math Journeys grade 2 program provides students with supports to connect, create, define, and explain concrete and representational models to abstract concepts, as required by the TEKS. In journey B3.10, “Sumamos por descomposición: llevadas en las unidades,” the
Teacher Guide provides questions, discussions, instructional supports, and a video resource to guide students through the progression from concrete models to pictorial representations and abstract mathematical concepts. In development activity 1, students use base 10 blocks to represent and solve 28 + 35, counting the tens and ones in each addend and combining them to determine the total. The
Teacher Guide explains that when the total number of ones exceeds nine, students may exchange 10 ones for one ten rod, reinforcing the relationship between ones and tens within the base 10 system. Students then create pictorial representations by drawing the base 10 blocks and recording the regrouping process, and they connect these representations to an abstract vertical addition model using decomposition. A supporting video further reinforces the concept by demonstrating addition problems in which the ones digits total more than nine and require regrouping. As students share and explain their representations, the educator ensures that the symbolic notation accurately reflects the exchange of 10 ones for one ten and prompts students to explain how the concrete model, drawing, and written algorithm represent the same mathematical process. These supports help students connect, create, define, and explain the relationships among concrete models, visual representations, and abstract mathematical procedures while developing a conceptual understanding of addition with regrouping.