UNIT 4 OVERVIEW In this unit students will: • continue to develop their understanding of and facility with addition and subtraction. add up to 4 two-digit numbers. • use a variety of models (base ten blocks- ones, tens, and hundreds only; diagrams; number lines; place value strategies; etc.) to add and subtract within one thousand. • become fluent with mentally adding or subtracting 10 or 100 to a given three-digit number. • demonstrate fluency with addition and subtraction. • understand the relationship between addition and subtraction (inverse operations). • represent three digit numbers with a variety of different models (base ten blocks- ones, tens, and hundreds only; diagrams; number lines; place value strategies; etc.). • recognize and use place value to manipulate numbers. • continue to develop their understanding of, and facility with, money. • count with pennies, nickels, dimes, and dollar bills. • represent a money amount with words or digits and symbols (either cent or dollar signs). • represent and interpret data in picture and bar graphs. • use information from a bar graph to solve addition and subtraction equations.
STANDARDS FOR MATHEMATICAL CONTENT Use place value understanding and properties of operations to add and subtract MGSE2.NBT.6 Add up to four two-digit numbers using strategies based on place value and properties of operations. MGSE2.NBT.7 Add and subtract within 1000, 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. MGSE2.NBT.8 Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or 100 from a given number 100–900. MGSE2.NBT.9 Explain why addition and subtraction strategies work, using place value and the properties of operations.
Work with time and money MGSE2.MD.8 Solve word problems involving dollar bills, quarters, dimes, nickels, and pennies, using $ and ¢ symbols appropriately. Example: If you have 2 dimes and 3 pennies, how many cents do you have?
Represent and interpret data MGSE2.MD.10 Draw a picture graph and a bar graph (with single-unit scale) to represent a data set with up to four categories. Solve simple put-together, take-apart, and compare problems 1 using information presented in a bar graph.
BIG IDEAS By the conclusion of this unit, students should be able to demonstrate the following competencies: • Know how to add up to 4 two-digit numbers • Be able to use a variety of models (base ten blocks- ones, tens, and hundreds only; diagrams; number lines; place value strategies; etc.) to add and subtract within one thousand • Mentally add or subtract 10 or 100 to a given three-digit number • Understand the relationship between addition and subtraction (inverse operations) • Represent three digit numbers with a variety of different models (base ten blocks- ones, tens, and hundreds only; diagrams; number lines; place value strategies; etc.) • Recognize and use place value to manipulate numbers • We can verify the results of our computation by using the inverse operation. • Estimation helps us see whether or not our answers are reasonable. • A numeral’s meaning and value is based upon where digits are placed to write the numeral. • Adding or subtracting ten from a given number changes the digit in the tens place of a given number but not the digit in the ones place of a given number. It also changes the value of the given number by either increasing or decreasing it in increments of ten. • Adding or subtracting 100 from a given number changes the digit in the hundreds place of that given number but not the digits in the tens and ones places of that given number. It also changes the value of the given number by either increasing or decreasing it in increments of 100. • Addition means the joining of two or more sets that may or may not be the same size. There are several types of addition problems, see the chart below. • Subtraction has more than one meaning. It not only means the typical “take away” operation, but also can denote finding the distance between two amounts, i.e. comparison. Different subtraction situations are described in the chart below. • Numbers may be represented in a variety of ways such as base ten blocks, diagrams, number lines, and expanded form. • Place value can help to determine which numbers are larger or smaller than other numbers. • Counting dollars is just like counting by ones and tens in our place value system. • Counting coins can be connected to how we count by ones, fives, and tens. • Count with pennies, nickels, dimes, and dollar bills • Represent a money amount with words or digits and symbols (either cent or dollar signs) • Interpret data in picture and bar graphs • Use information from a bar graph to solve addition and subtraction questions and equations