1.NBT.C.6 Teacher Editions
CCSS.MATH.CONTENT.1.NBT.C.6
:"Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used."
These teacher editions can help students practice this Common Core State Standards skill.
