# Second Grade Math 2016-17

## Teacher/Student Resources

Envision

Topic 1 Videos- 5 lessons of addition

Topic 2 Videos- 6 lessons of subtraction

Topic 5 Videos- 8 lessons of addition & subtraction

Topic 6 Videos- 8 lessons of adding 2 digit numbers (6.6 adding on a number line)

Topic 7 Videos- 9 lessons of subtracting 2 digits (7.6 subtracting on a number line)

Topic 11 Videos- Even odd, 10 more & 10 less, & finding patterns

Vocabulary

Addition, sum, place value, digit, difference, subtraction, strategy, strip diagram, ones, tens, hundreds, algorithm, greater than (>), less than (<), number line, open number line, approximately, estimation, 10 less, 10 more, 100 less, 100 more, value of a number, digit, number sentence, unknown, basic facts, equation, & problem situations

Language Objective:

I will use a problem-solving strategy to solve my addition problem and share it with my shoulder partner by using the sentence stem:

“I added ___ + ___ using the (make a drawing) strategy and my answer is ___.” (ELPS 3C)

I understand what fact families are and I can explain it by using the sentence stem:

“Numbers __,__, and __ are a fact family.” (ELPS 3B, 3C)

Vocabulario

sumar, adición, valor de posición, dígito, la diferencia, la resta, unidades, decenas, centenas, estrategia, diagrama de tira, algoritmo, aproximadamente, conjuntos equivalentes, 10 más, 10 menos, 100 más, 100 menos, un poco más que, valor de un número, operaciones básicas, relación invertida, recta numérica, mayor que (>), menor que (<), oración numérica, ecuación, y los problemas relevantes.

Objetivo del Lenguaje:

Yo utilizo una estrategia de resolución de problemas para resolver la suma y se la explico a mi compañero con la oración:

“Yo sumé ___ + ___ utilizando la estrategia ___ (hacer un dibujo) y mi respuesta es ___.” (ELPS 3C)

Yo comprendo lo que son las operaciones básicas y digo los números de la familia de operaciones con la oración:

“Los números __,__ y __ son una familia de operaciones.” (ELPS 3B, 3C)

Essencial Question

What strategies may I use to solve addition and subtraction problems?

Sample sentence stems:

I agree because….

I disagree because….

What did you do to get that answer?

Can you show me how you did that?

Assessment

Envision 2.0:

Teacher’s Resource Masters Volume 1A

• Topic 1 Test

• Basic-Facts Timed Tests 1-6

• Topic 2 Test

## 2.4 Number and operations. The student applies mathematical process standards to develop and use strategies and methods for whole number computations in order to solve addition and subtraction problems with efficiency and accuracy. The student is expected to: 2.4A recall basic facts to add and subtract within 20 with automaticity.

What does recalling facts with automaticity mean? It means that students can recall their basic facts within about 3 seconds and without counting.

When students begin to learn their basic facts, they tend to go through 3

developmental stages:

1. Students begin adding and subtracting by counting. Hopefully, much of this stage is completed in Kindergarten and 1st grade.

2. The second phase is called “reasoning.

3. Finally, students can retrieve their facts from their long-term memory with ease.

This can be supported with free and fun computer games on the Internet. Kids love to play games. Let them play! ## 2.4 Number and operations. The student applies mathematical process standards to develop and use strategies and methods for whole number computations in order to solve addition and subtraction problems with efficiency and accuracy. The student is expected to: 2.4C solve one-step and multi-step word problems involving addition and subtraction within 1,000 using a variety of strategies based on place value, including algorithms.

Students should experience story problems while they are learning the operations, rather than not getting story problems until later.

Example/Activity

Refer back to the base ten block example from 2.4B (see picture below). This method uses place value to help student bridge from the concrete models to a flexible algorithm, and finally to the traditional algorithm.

Strategies could also include place value combined with properties of operations. For instance, students could decompose the problem into place values.

546 + 252 is (500 + 200) + (40 + 50) + (6 + 2).

If your students are unsure about whether to add or to subtract, have them act the story out. Are they putting things together, or are they taking them apart? Those actions determine the operation to use.

Remember that sometimes subtraction problems may be solved by adding up, which seems more like addition than subtraction. That’s okay! As long as their explanations make sense, let them use their strategy to solve the problem.

It is not enough that students solve a problem. They must be asked to justify their answer too. Both right answers and wrong answers need to be justified. When you ask a student to justify a correct answer, the student thinks that he or she is wrong and changes the answer. At that point, you need to reassure the student that you are asking for justification for every answer, right or wrong. The second thing that may happen is that a student who is justifying an incorrect answer may

begin the justification and realize his or her mistake.

Guiding Questions for Justification:

• How does your answer relate to the story in the problem?

• What does your number stand for? What is its unit or label?

• Explain why you added (subtracted).

• What did you do wrong? How did you correct it? ## 2.4 Number and operations. The student applies mathematical process standards to develop and use strategies and methods for whole number computations in order to solve addition and subtraction problems with efficiency and accuracy. The student is expected to: 2.4D generate and solve problem situations for a given mathematical number sentence involving addition and subtraction of whole numbers within 1,000.

Students should initially be allowed to work in groups to write the problem situations. They need to justify why their problem situation matches the number sentence. Students should also be challenged to write problem situations that do not match the number sentence. The unknown in the number sentence can be any one of the

terms.

Example:

158 + 644 = q

Students must think of a problem situation that matches. An example of a correct situation might be, “Great Elementary has 158 students in 2nd grade. There are 644 students in the other grades. How many students go to school at Great Elementary?”

Some problem situations that students generate may be more difficult to assess. For example, students are given the number sentence:

925 - q = 742

The goal for the problem situations that students create is that they match the intent of the number sentence, not just the numbers in the sentence.

## 2.7 Algebraic reasoning. The student applies mathematical process standards to identify and apply number patterns within properties of numbers and operations in order to describe relationships. The student is expected to: 2.7C represent and solve addition and subtraction word problems where unknowns may be any one of the terms in the problem.

Students represent problems with objects, manipulat ives, diagrams, language, and numbers.

They may be expected to solve problems using number sense, mental math, and algorithms based on place value and properties of operations.

To solve a problem the number sentence can be written in more than one way.

67 – 29 = q

29 + q = 67

67 - q = 29

q + 29 = 67

Number Sense/Mental Math:

29 + q = 67

Think:

29 is close to 30.

30 + 37 = 67.

Since I used 30 instead of 29 and 30 is one more than 29, I will need one more than 37 for my answer. My answer is 38.

Use the same number sets that students are using with operations in second grade: up to 1,000. ## Lucy Doggett

Hope you find this letter helpful. Please feel free to contact me if questions or suggestions.