Unit 6

Place Value, Comparison, Addition, and Subtraction to 100

 

Grade 1

Math

 

 

Description:  The students will focus on “adding and subtracting within 100. The new level of complexity is to build off the place value understanding and mental math strategies that were introduced earlier. Students explore by using simple examples and the familiar units of 10 made out of linking cubes, bundles, and drawings. Students also count to 120 and represent any number within that range with a numeral.

 

Louisiana Student Standards for Mathematics (LSSM)

Instructional Outcomes

 

Operations and Algebraic Thinking

Represent and solve problems involving addition and subtraction.

1.OA.1

 

Use addition and subtraction within 20 to solve word problems involving situations of adding

to, taking from, putting together, taking apart, and comparing, with unknowns in all positions,

e.g., by using objects, drawings, and equations with a symbol for the unknown number to

represent the problem.

Numbers and Operations in Base Ten

Extending the Counting Sequence

1.NBT.1

 

 

Count to 120, starting at any number less than 120.  In this range, read and write numerals and represent a number of objects with a written numeral.

Understand Place Value.

1.NBT.2

 

 

Understand that the two digits of a two-digit number represent amounts of tens and ones. 

1.NBT.3

 

 

Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.

Use Place Value Understanding and Properties of Operations to Add and Subtract.

1.NBT.4

 

 

Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10.

a. Use 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 number sentence; justify the reasoning used with a written explanation.

b. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.

1.NBT.5

 

 

Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

1.NBT.6

 

 

 

 

Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero difference), 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 and explain the reasoning used.

Measurement

Work with Money

1.MD.5

Determine the value of a collection of coins up to 50 cents. (Pennies, nickels, dimes and quarters in isolation; not to include a combination of different coins.)

 

Enduring Understandings:

·         Students will solve different types of addition and subtraction word problems and equations using different strategies. 

·         Place value can be used to compare two numbers. 

·         Students will add two-digit and one-digit numbers with and without composing a group of ten.

·         Students will represent numbers greater than 10 as the sum of all the tens and the ones.

·         Numbers greater than 10 can be named in more than one way.

 

Essential Questions:

·         What happens when we join two quantities or take one from another?

·         How can we find the total when we join two quantities?

·         How can we find what is left when we take one quantity from another?

·         How can we find the difference when we compare one quantity to another?

·         How can we compare one quantity to another?

·         How can I solve different types of addition and subtraction word problems using different strategies?

·         How do I explain my answer so that others understand my thinking?