In Grade 1, students build fluency with adding within 100, using models or drawings and strategies based on place value, properties of operations, and the relationship between addition and subtraction. The tabs identify key strategies for adding and subtracting two-digit numbers and a link to a document that fully describes and illustrates these strategies.
Addition Strategies Based on Place Value and Properties of Operation
Fluency is grounded in understanding. Developing an understanding of two-digit addition begins with physical models and progresses to connecting physical and visual models to numeric representations. The learning targets for 1.NBT.4 identify the following tools, models, and strategies that students should use to build fluency with addition:
Explain addition using physical tools, hundred charts, drawings, and number lines
Add using partial sums when decomposing both addends
Add using count on when decomposing one addend
Adjust numbers to add more efficiently (pictured)
For full descriptions and illustrations of these strategies, download the file linked below:
Subtraction Strategies Based on Place Value and Properties of Operations
*Note: this section applies to 1st grade students learning 2nd grade standards**
Fluency is grounded in understanding. Developing an understanding of two-digit and three-digit subtraction begins with physical models and progresses to connecting physical and visual models to numeric representations. The learning targets for 2.NBT.5 and 2.NBT.7 identify tools, models, and strategies that students should use to build fluency with subtraction:
Explain subtraction using physical tools, hundred charts, drawings, and number lines
Find the difference of two numbers by counting up or by counting back
Subtract using partial differences when decomposing the subtrahend (pictured)
Adjust numbers to subtract more efficiently
For full descriptions and illustrations of these strategies, download the file linked below: