

Unit 4 Addition and Subtraction Within 200 with Word
Problems to 100 Grade 2 Math 


Description: In Unit
4, students work to build fluency in twodigit addition and subtraction
within 100 and apply fluency to one to twostep word problems within 100. Building
fluency supports students to utilize opportunities to see and analyze the
relationships between quantities. Students develop conceptual understanding
of addition and subtraction of multidigit numbers within 200 as a foundation
for work with addition and subtraction within 1,000 in Unit 5. 

Louisiana Student Standards for Mathematics
(LSSM) 





Enduring Understandings: ·
When one quantity is joined or added on to
another quantity, the result is greater than or equal to the initial
quantity. • When one quantity is removed
from another quantity, the result is less than or equal to the initial
quantity. ·
Joining,
removing, partpartwhole, and comparing problems can be modeled. ·
Addition
and subtraction can be composed and decomposed to simplify the operation. ·
Mental
math strategies may be used to solve problems involving numbers. ·
Problems
can be solved in a variety of ways such as modeling, number bonds, tape
diagrams, counting strategies, or standard algorithms. ·
Problems and solutions can use various
representations, including concrete objects, pictures, number sentences, and
words. 
Essential Questions: ·
How do we use addition and subtraction to tell
number stories? ·
How does using ten as a benchmark number help us
add and subtract? ·
How can we solve addition problems with and without
composing? ·
How can we solve subtraction problems with and without
decomposing? ·
How can strategies help us when adding and subtracting?
·
How are addition and subtraction alike and how
are they different? ·
How do we solve problems in different ways? ·
How can problem situations and problemsolving
strategies be represented? ·
How are problemsolving strategies alike and different?



