2nd Math Numbers and Operations Base 10

I-CANyons Parent Toolkit for Second Grade Mathematics

Numbers and Operations in Base 10: I CAN...

Standard

Core Standard

In Other Words...

If Mastered

If Not Yet Mastered

Understand place value to the hundreds place

NBT 2.1. Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Understand the special cases: a. 100 can be though of as a bundle of ten tens - called a "hundred" b. The numbers 100, 200, 300, 400, 500,600,700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds (and 0 tens and 0 ones)

Second Grade students extend their base-ten understanding to hundreds and the idea that 10 tens make a “hundred”. Multiples of 100 (200, 300, etc) are simply groups of "hundreds".

If your child can quickly build, read, write, and count numbers to 100 your may want to use larger numbers. If you feel like your child has good place value understanding begin to ask questions such as, What is ten more than 29? or Which number is 10 less than 99? or Which numbers have more than 5 tens and less than 7 tens? Another activity that you could do with your child is to use a hundreds chart and play "Guess my Number." Provide clues such as, "I have 4 tens, I am odd, I am less that 45, and I have more than 1 one. What number am I?" [43]. With each clue the child would cross off incorrect number. When the mystery number is guessed, ask the child to describe the number in different ways, such as four tens and three ones or forty and three.
Linked is an activity that composes numbers according to place value
Click here for the activity.

Find a collection of items that your child may be interested in counting. The quantity of objects should not be more that 100. Ask the question, "How could we count our buttons in some way that would be easier than counting by ones?" Whatever suggestions you get try to implement them. After trying several ways, you can have a discussion on what worked well and what did not. If your child did not suggest counting by tens, you may suggest trying it. An activity your may use with your child if you feel he/she is gaining an understanding of plave value is: Jan has 3 number cards 8 6 3
What is the largest three-digit number Jan can make with these cards? How can you show that this number is the largest number she can make? Explain your answer.
•Then Jan rolled three numbers with her dice. They are:
2 5 7
What is the smallest three-digit number Jan can make with these numbers? How can you show that this number is the smallest number she can make?

Standard

Core Standard

In Other Words

If Mastered

If Not Yet Mastered

Count read and write numbers to 1000

NBT 2.2. Count within 1000; skip-count by 5s, 10s, and 100s.

NBT 2.3 Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.

NBT 2.2
Second Grade will be able to count by 5s, 10s, and 100s up to 1000.

NBT 2.3
Students will be able to read and write numbers in the following ways: A. 987 (standard form), B. nine hundred eighty seven (word form) ** Note the avoidance of the term "and", C. 900 + 80 + 7 (expanded form)

NBT 2.2
Have students start at a random number and count on by 5's, 10's, or 100's
Provide games and other situations that allow students to practice skip-counting. Students can use nickels, dimes and dollar bills to skip count by 5, 10 and 100. Pictures of the coins and bills can be attached to models familiar to students: a nickel on a five-frame with 5 dots or pennies and a dime on a ten-frame with 10 dots or pennies.
•http://www.ixl.com/math/grade-2

NBT 2.3
Students can represent one number in multiple ways. They will understand that there are multiple ways to express a given number (base ten, number name, expanded form).
Students will understand what expanded form is.
Students will understand how to change numbers easily back and forth from standard form (364) to expanded form ( 300+60+4) to written form three hundred sixty-four.

NBT 2.2
Use ten frames and count on:
•http://www.k-5mathteachingresources.com/support-files/skipcountingcards.pdf
•http://www.ixl.com/math/grade-2/skip-counting
•http://www.ixl.com/math/grade-2/skip-counting-sequences
•http://www.ixl.com/math/grade-2/counting-patterns-up-to-100
•Using the 200 board (http://elemed.ucps.k12.nc.us/parent_resources/PA%202_2_1%20200Chart.pdf, last page) students will have the student color in red all 5s,
color in blue all 10s, and colorin green all 100s on the 200 board
• If students are still struggling they can count by 5's using their fingers.

NBT 2.3
Use candy or other manipulatives to solve this problem: Suzie went trick-or-treating and collected 238 pieces of candy. Show three different examples of how Suzie could represent how much candy she collected using examples of standard form, word form, or expanded form. Place value (hundreds, tens, and ones) Or draw pictures to show the numbers. Write numbers in different ways on cards and have the students play a matching game: 1,645 will match 1,000 +600+ 40+5. and so on. http://www.ixl.com/math/grade-2/convert-from-expanded-form-up-to-thousands

Standard

Core Standard

In Other Words

If Mastered

If Not Yet Mastered

Count read and write numbers to 1000

NBT 2.2. Count within 1000; skip-count by 5s, 10s, and 100s.

NBT 2.3 Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.

Standard

Core Standard

In Other Words

If Mastered

If Not Yet Mastered

Compare 3-digit numbers using symbols

NBT 2.4 Compare two three-digit numbers based on meanings of the hundreds, tens, and ones digits, using >, =, and < symbols to record the results of comparisons.

Second grade students will apply their understanding of place value and will use the following symbols and their meanings to compare three-digit numbers: > is greater than, = is equal to, < is less than. For example: 187 < 193; students say, "one hundred eighty seven is less than one hundred ninety three.

Student will explain 412<491
412 is, in fact, less than 491. Although both numbers have four 100s (fours in the hundred’s place), 412 only has one ten (a one in the ten’s place), while 491 has nine tens (a nine in the ten’s place). Game : Use deck of cards, stacked in the middle. Play a war card game. Each person chooses 2 cards and compares it to a friend. The one with the greater card says number sentences. Students can also start comparing equations ( http://www.sheppardsoftware.com/mathgames/fruitshoot/FruitShootCompareM.htm )

Comparing numbers website
•http://real.doe.k12.ga.us/content/math/destination_math/MSC2/msc2/msc2/msc2/msc2/module1/unit1/session5/lesson.html?
•Place value challenge (http://www.k-5mathteachingresources.com/support-files/placevaluechallenge3digits.pdf)

Standard

Core Standard

In Other Words

If Mastered

If Not Yet Mastered

Add or subtract to 1000 using models

NBT 2.7 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. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

Second graders begin adding and subtracting to 1000 using models. Students should have ample experiences using hands-on materials such as place value blocks and drawing the math problem in pictures to support their work.
This standard also references composing and decomposing which means regrouping to be able to add or subtract.

Have the student orally explain every step while adding and subtracting three digit story problems. Possible Activities:
Click here for the following games:
2 Digit Addition Trains
2 Digit Addition Trains (with exchanging)
Base Ten Pictures
Base Ten Bag: Addition
Base Ten Bag: Subtraction

Base Ten Buildings
3 Digit Addition Split
3 Digit Subtraction Split
Friendly Numbers: Subtraction Two-Digit addition and subtraction word problems

Three-Digit addition and subtraction problems

Example: 354 + 287 = __ Have your student solve this problem on a number line. Saying: "I started at 354 and jumped 200. I landed on 554. I then made 8 jumps of 10 and landed on 634. I then jumped 7 to land on 641. Example: 213 - 124 = __ Student saying "I used place value blocks. I made a pile of 213. I then started taking away blocks. First, I took away a hundred. Then I took away 2 tens. Last I took away 4 ones. I was left with 8 tens and 9 ones, so my answer is 89. web site to help add numbers to 1,000
Add Numbers up to 1,000

Regrouping 10s and 1s

Standard

Core Standard

In Other Words

If Mastered

If Not Yet Mastered

Understand addition to 1000 using models

Second grade students will use their understanding of place value, the connection between addition and subtraction ( 3 + 4 = 7; 7 - 4 = 3), and the properties of addition (Commutative: 123 + 457 = 457 + 123) and [Associative: (47 + 23) + 75 = 47 +( 23 + 75)] to be able to add within 1000. Composing (making groups of 10 ones, tens, or hundreds) and decomposing (breaking apart hundreds and tens into groups of 10) may be required.

Have the student orally explain every step while adding and subtracting three digit story problems.
http://www.k-5mathteachingresources.com/2nd-grade-number-activities.html
Possible Activities:
2 Digit Addition Trains
2 Digit Addition Trains (with exchanging)
Base Ten Pictures
Base Ten Bag: Addition
Base Ten Bag: Subtraction

Base Ten Buildings
3 Digit Addition Split
3 Digit Subtraction Split
Friendly Numbers: Subtraction http://www.ixl.com/math/grade-2/addition-3-digits-word-problems http://www.ixl.com/math/grade-2/subtraction-3-digits-word-problems

Standard

Core Standard

In Other Words

If Mastered

If Not Yet Mastered

Understand subtraction to 1000 using models.

Standard

Core Standard

In Other Words

If Mastered

If Not Yet Mastered

Fluently add two-digit numbers

NBT 2.5 Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

NBT 2.6 Add up to four two-digit numbers using strategies based on place value and properties of operations

The following websites provide activities to extend students' understanding of the standard:http://www.uen.org/Lessonplan/preview.cgi?LPid=21446, http://commoncoretasks.ncdpi.wikispaces.net/2.NBT.5-2.NBT.9+Tasks

Use base blocks addition to build a concrete understanding of 2 digit addition http://nlvm.usu.edu/en/nav/category_g_1_t_1.html

Standard

Fluently subtract two-digit numbers

Core Standard

NBT 2.5
Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

NBT 2.7 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. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

In Other Words

Second grade students will apply their understanding of place value, properties of operations, and the relationship between addition and subtraction to fluently (without hesitation) add and subtract within 100. Second grade students will use their understanding of place value, the connection between addition and subtraction ( 3 + 4 = 7; 7 - 4 = 3), and the properties of addition (Commutative: 123 + 457 = 457 + 123) and [Associative: (47 + 23) + 75 = 47 +( 23 + 75)] to be able to add within 1000. Composing (making groups of 10 ones, tens, or hundreds) and decomposing (breaking apart hundreds and tens into groups of 10) may be required.

If Mastered

The following websites provide opportunities for students to extend their understanding of this standard: http://www.insidemathematics.org/assets/common-core-math-tasks/sheep%20and%20ducks.pdf http://s3.amazonaws.com/illustrativemathematics/illustration_pdfs/000/001/063/original/illustrative_mathematics_1063.pdf?1390748387

If Not Yet Mastered

Common Misconceptions
Students may think that the 4 in 46 represents 4, not 40. Students need many experiences representing two-and three-digit numbers with objects and models. When adding two-digit numbers, some students might start with the digits in the ones place and record the entire sum. Then they add the digits in the tens place and record this sum. Provide many experiences modeling addition with objects. When subtracting two-digit numbers, students might start with the digits in the ones place and subtract the smaller digit from the larger digit. Then they move to the tens and the hundreds places and subtract the smaller digits from the larger digits. Assess students’ understanding of place value, for example, 13 is made up of 1 ten and 3 ones.
•http://www.ixl.com/math/grade-2/subtract-two-digits
• http://www.ixl.com/math/grade-2/subtract-two-two-digit-numbers-with-regrouping
•http://www.ixl.com/math/grade-2/addition-3-digits-add-two-numbers