Which One Doesn’t Belong: First Grade
Common Core State Standards
Math 
Math 
1 
Grade 1 
NBT 
Number & Operations in Base Ten 
B 
Understand place value 
2a 
Understand that the two digits of a twodigit number represent amounts of tens and ones. Understand the following as special cases: a. 10 can be thought of as a bundle of ten ones  called a "ten." b. The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones. c. The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones). 
Download Common Core State Standards (PDF 1.2 MB) 
Common Core State Standards
Math 
Math 
1 
Grade 1 
NBT 
Number & Operations in Base Ten 
B 
Understand place value 
2b 
Understand that the two digits of a twodigit number represent amounts of tens and ones. Understand the following as special cases: a. 10 can be thought of as a bundle of ten ones  called a "ten." b. The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones. c. The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones). 
Download Common Core State Standards (PDF 1.2 MB) 

Lesson Idea (Common Core)Counting Collections to 100Grades K2 / Math / AdditionMath.1.NBT.C.4 / Math.1.NBT.C.5
 187
 19

Tch SpecialAddition Number Talk: First GradeGrade 1 / Math / Tch DIYMath.1.NBT.C.4

Lesson Idea (Common Core)Leprechaun Traps: Addition Within 100Grades K2 / Math / ReasoningMath.1.NBT.C.4 / Math.Practice.MP2 / Math.Practice.MP3
 529
 61

Lesson Idea (Common Core)Making Math Fun with Place Value GamesGrade 2 / Math / Place ValueMath.2.NBT.A.4 / Math.2.NBT.B.5 / Math.2.NBT.A.1a
 555
 126

Tch SpecialMultiplication Number Talk: Third GradeGrade 3 / Math / Tch DIYMath.3.OA.B.5 / Math.3.NBT.A.3
 20
 8

Tch SpecialMultiplication Number Talk: Fourth & Fifth GradeGrades 45 / Math / Tch DIYMath.4.NBT.B.5
 21
 10

Lesson Idea (Common Core)Beyond Fingers: Place Value & the Numbers 1119Grades K2 / Math / ReasoningMath.K.NBT.A.1 / Math.Practice.MP2 / Math.Practice.MP3
 638
 94

Lesson Idea  Common CoreEngaging in Productive Struggle: Number TalksGrade 2 / Math / ELLMath.2.NBT.B.5 / Math.Practice.MP1 / Math.Practice.MP3
 1K
 41
A "Which One Doesn't Belong" routine encourages students to reason about the similarities and differences among a set of numbers, expressions, shapes, or images.
Tch visited Kristin's Gray's school. Watch the video.
Teacher & School Info

Kristin Gray
 School Details
 Shields (Richard A.) Elementary School Lewes, DE
 Population
 722 students
 District Spending
 $14,381
Supporting Materials

Lesson Plan: Which One Doesn't Belong Planning Guide.PDF

Reflection and Resources.PDF