Mental Math

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Grade 2 Topics

1 Introduction to Addition and Subtraction
- 1.1 Addition Sentences
- 1.2 Addition Stories
- 1.3 Subtraction Sentences
- 1.4 Subtractions by Separating
- 1.5 Making Comparisons

2 Addition and Subtraction
- 2.1 Connecting Adding and Subtracting
- 2.2 Inverse Relation of Addition to Subtraction
- 2.3 Inverse Relation of Subtraction to Addition
- 2.4 Balance Equation of Addition and Subtraction
- 2.5 Using Objects in Problem Solving

3 Addition
- 3.1 Addition
- 3.2 Single Digit Number Addition
- 3.3 Adding Objects
- 3.4 Doubling Numbers
- 3.5 Using Near Doubles
- 3.6 Order in Addition

4 Concepts of Addition
- 4.1 Add 9
- 4.2 Add 8
- 4.3 Balancing Addition Equation
- 4.4 Using Numbers to Solve Addition Sentences
- 4.5 Balance Addition Equations

5 Subtraction
- 5.1 Subtraction
- 5.2 Subtracting One-Digit Numbers
- 5.3 Using Subtraction to Check Addition
- 5.4 Using Addition to Check Subtraction
- 5.5 Subtraction Sentences Using Pictures

6 Concepts of Subtraction
- 6.1 Using Addition Double to Help You Subtract
- 6.2 Using Addition Facts to Help You Subtract I
- 6.3 Using Addition Facts to Help You Subtract II
- 6.4 Use Subtraction to Find the Missing Part
- 6.5 Balance Subtraction Equation
- 6.6 Complete Subtraction Sentences
- 6.7 Two Questions Problem Solving

7 Learn Place Value up to 100 Part I
- 7.1 Place Value Models
- 7.2 Place Value Models for Tens
- 7.3 Numbers Using Place Value Models
- 7.4 Compare Numbers Using Models
- 7.5 Compare Numbers Using Symbols
- 7.6 Numbers: Before, After, and in Between

8 Learn Place Value up to 100 Part II
- 8.1 Identifying Number Pattern on a Hundred Chart
- 8.2 Understanding Number Order
- 8.3 Even and Odd Numbers
- 8.4 Identify Digits in Tens and Ones Place
- 8.5 Regroup Tens and Ones
- 8.6 Place Value in Addition
- 8.7 Using Data from a Chart

9 Counting Money Part I
- 9.1 Identify the Values and Names of Coins
- 9.2 Count Dimes, Nickels, and Pennies
- 9.3 Count Quarters and Half-Dollars
- 9.4 Count Group of Different Coins
- 9.5 Converting Cents to Dollars

10 Counting Money Part II
- 10.1 Dollars to Cents Conversion
- 10.2 Different Ways to Make the Same Amount
- 10.3 Using Least Number of Coins
- 10.4 Using One Dollar
- 10.5 Amounts of Change from Purchase
- 10.6 Solving Story Problems

11 Exploring Mental Addition
- 11.1 Add by Tens
- 11.2 Add by Ones
- 11.3 Add by Tens and by Ones
- 11.4 How to Use a Hundred Chart
- 11.5 Add Numbers Ending in Zero
- 11.6 Looking for Pattern in Problem Solving

12 Exploring Mental Subtraction
- 12.1 How to Subtract by Tens
- 12.2 Make One Hundred
- 12.3 Using the Hundred Chart to Subtract
- 12.4 Use Addition to Subtraction
- 12.5 Subtracting Multiples of 10
- 12.6 Solving Problems

13 Two-Digit Number Addition
- 13.1 Using Regrouping in Addition
- 13.2 Models for One-Digit Number Addition
- 13.3 Add One-Digit and Two-Digit Numbers
- 13.4 Modeling Adding Two-Digit Numbers
- 13.5 Adding Two-Digit Numbers
- 13.6 Complete Addition Sentences
- 13.7 Add Vertically and Horizontally
- 13.8 Three Number Additions
- 13.9 Use Pictures and Write Number Sentences in Problem Solving

14 Use of Addition and Subtraction
- 14.1 Adding Money
- 14.2 Estimate the sums
- 14.3 Exploring Ways to Add
- 14.4 Subtracting Money
- 14.5 Estimate the Differences
- 14.6 Identifying Ways to Subtract
- 14.7 Guess and Try, Checking, and Revising in Problem Solving

15 Introduction to Geometry Part I
- 15.1 Introducing Vertices, Edges, and Faces
- 15.2 Identifying Plane Shapes
- 15.3 Identifying Solid Figures
- 15.4 Identify 2 and 3 Dimensional Shape and Solids
- 15.5 Connecting Plane Shapes to Solid Figures
- 15.6 Connecting Shapes

16 Introduction to Geometry Part II
- 16.1 Cutting Shapes Apart in Geometry
- 16.2 Identifying Congruence
- 16.3 Slide, Rotate, and Flip Shape
- 16.4 Identifying Symmetry
- 16.5 Using Reasoning in Problem Solving

17 Understanding Fractions
- 17.1 Parts of a Whole
- 17.2 Unit Fractions
- 17.3 Non-Unit Fractions
- 17.4 Estimate the Fraction of a Whole
- 17.5 Find the Fractions in a Group
- 17.6 Use Fractions to Solve Problems
- 17.7 Ordering and Comparing Fractions

18 Measurement: Length, Area, and Perimeter
- 18.1 Attributes of Measurement
- 18.2 Measure Length
- 18.3 Measure Length: Use Non-Standard Unit
- 18.4 Use Inches, Feet, and Yards to Measure Length
- 18.5 Use Centimeters and Meters in Measure Length
- 18.6 Compare and Convert Meter, Centimeter, and Millimeter
- 18.7 Perimeter
- 18.8 Area
- 18.9 Using Objects in Problem Solving

19 Measurement: Weight and Capacity
- 19.1 Measuring Capacity
- 19.2 Understanding Cups, Pints, and Quarts
- 19.3 Compare and Convert Cups, Pints, and Quarts
- 19.4 Understanding Liter and Milliliter
- 19.5 Compare and Convert Liter and Milliliter
- 19.6 Measuring Weight
- 19.7 Understanding Pounds and Ounces
- 19.8 Compare and Convert Pounds and Ounces
- 19.9 Understanding Grams and Kilograms
- 19.10 Compare and Convert Grams and Kilograms
- 19.11 Using Objects in Problem Solving

20 Understand Time and Temperature Part I
- 20.1 Time Related Words
- 20.2 Hour, Half-hour, and Quarter-hour
- 20.3 Tell Time to Nearest Hour, Half-hour, and Quarter-hour
- 20.4 Tell Time at Five Minute Intervals
- 20.5 Time Before and After the Hour

21 Understand Time and Temperature Part II
- 21.1 Estimate Elapsed Time
- 21.2 Read the Calendar
- 21.3 Read Temperature in Fahrenheit and Celsius
- 21.4 Relate Time Units
- 21.5 Problem Solving

22 Probability, Data, and Graphs
- 22.1 Data and Graphing Data
- 22.2 Interpret Pictographs
- 22.3 Use Bar Graphs
- 22.4 Explore Coordinate Graphs
- 22.5 Likely and Unlikely Events
- 22.6 Identifying Certain, Probable, and Impossible Events
- 22.7 Using Data in Problem Solving
- 22.8 Find Median, Mode, and Range

23 Understanding Patterns and Numbers to 1,000 Part I
- 23.1 Read and Write Numbers to 1,000
- 23.2 Count by Hundreds, Tens, and Ones
- 23.3 Reading and Writing Numbers to 1,000
- 23.4 Change the Numbers by Tens and Hundreds
- 23.5 Identify Number Patterns on Hundred Chart
- 23.6 Numbers Comparison

24 Understanding Patterns and Numbers to 1,000 Part II
- 24.1 Numbers: Before, After, And in Between
- 24.2 Order of Numbers
- 24.3 Skip Counting
- 24.4 Estimating and Rounding to Nearest 10
- 24.5 Estimating Sum of Two Numbers
- 24.6 Looking for Patterns in Problem Solving

25 Three-Digit Addition and Subtraction
- 25.1 Using Mental Math
- 25.2 How to Estimate Sums
- 25.3 Using Models for Three-Digit Number Addition
- 25.4 Exploring Adding Three-Digit Numbers
- 25.5 Finding Missing Parts Using Mental Math
- 25.6 Estimate the Differences
- 25.7 Identifying Models for Subtraction
- 25.8 Subtraction Using Three-Digit Numbers
- 25.9 Compare Addition and Subtraction Sentences
- 25.10 Balance Addition and Subtraction Sentences
- 25.11 Making Graphs in Solving Problems

26 Introducing Multiplication
- 26.1 Understanding Multiplication as Repeated Addition
- 26.2 Multiplication Facts of 0 to 2
- 26.3 Multiplication Facts of 3 to 5
- 26.4 How to Build Arrays
- 26.5 Stories of Multiplication
- 26.6 Vertical Form of Multiplication
- 26.7 Exploring Multiplication in any Order
- 26.8 Multiplication by Using Number Line
- 26.9 Draw Pictures and Write Multiplication Sentences

27 Introducing Division
- 27.1 Understanding Division as Sharing
- 27.2 Understanding Division as Repeated Subtraction
- 27.3 Stories Using Division
- 27.4 Division by Using a Number Line
- 27.5 Divisors and Quotients
- 27.6 Relating Multiplication and Division
- 27.7 Make a Table and Look for a Pattern

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Lily has a collection of marbles in different colors: 5 red, 6 yellow, 8 blue, and 4 green. Look at the tally charts below.

Which tally chart shows the correct number of marbles for each color?

Correct answer is

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