# Math: Relating Addition and Subtraction

### Suggested Time Frame: 14 Instructional Days

##### Focus TEKS

• 1.3D Apply basic fact strategies to add and subtract within 20, including making 10 and decomposing a number leading to a 10
• 1.5F  Determine the unknown whole number in an addition or subtraction equation when the unknown may be any one of the three or four terms in the equation
• 1.5G  Apply properties of operations to add and subtract two or three numbers

Addition and Subtraction – Problem Solving

• 1.3B  Use objects and pictorial models to solve word problems involving joining, separating, and comparing sets within 20 and unknowns as any one of the terms in the problem such as 2 + 4 =___; 3 +___= 7; and 5 =___– 3
• 1.3F Generate and solve problem situations when given a number sentence involving addition or subtraction of numbers within 20

Addition and Subtraction – Representing and Explaining

• 1.3E  Explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences
• 1.5D  Represent word problems involving addition and subtraction of whole numbers up to 20 using concrete and pictorial models and number sentences
##### Computational Fluency TEKS

Concept of Equality

• 1.5E  Understand that the equal sign represents a relationship where expressions on each side of the equal sign represent the same value(s)

• 1.3D Apply basic fact strategies to add and subtract within 20, including making 10 and decomposing a number leading to a 10 [Count On, Use Doubles, and Make Ten strategies in this unit]
##### Spiral Review TEKS

Place Value Concepts

• 1.2C  Use objects, pictures, and expanded and standard forms to represent numbers up to 120 [99]
• 1.2A  Recognize instantly the quantity of structured arrangements
• 1.2B  Use concrete and pictorial models to compose and decompose numbers up to 120 [99] in more than one way as so many hundreds, so many tens, and so many ones

Counting Collections

• 1.5A Recite numbers forward and backward from any given number between 1 and 120
• 1.5B  Skip count by twos, fives, and tens to determine the total number of objects up to 120 in a set;