Arrays for multiplication (age 7+)

CONCEPTUAL

Mathematics›Multiplication & Division|Ages 7—8|ID: mt_B1zj1RwQ3a

Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and 5 columns; write an equation to express the total as a sum of equal addends

Mastery Evidence

Count objects in a 3×4 array and write 4 + 4 + 4 = 12
Explain that each row has the same number of objects so the total can be found by repeated addition
Draw a rectangular array to model a given repeated-addition equation

Assessment Prompt

“If [child] sees 4 rows of 5 stickers on a sheet, can they use repeated addition — '5 + 5 + 5 + 5' — to find the total, and write it as an equation?”

Curriculum Standards1 alignment

2.OA.4Common Core State Standards for Mathematics

Use addition for rectangular arrays

Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.

Operations and Algebraic Thinking

Prerequisites2

Arrays for multiplication
hardAges 5—6
Multiplication as repeated addition
hardAges 5—6

Show full prerequisite tree

Arrays for multiplication hard
Rectangular arrays with repeated addition extends array representation from Y2
- Division as equal sharing hard
  Using arrays for division requires understanding division as grouping
  - Subtraction as taking away or separating hard
    Division as equal sharing/grouping requires understanding subtraction as taking away/separating
    - How Many in Total? hard
      Understanding subtraction as taking away requires knowing numbers represent quantities (cardinality)
      - One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
- Multiplication as repeated addition hard
  Using arrays requires understanding what multiplication means
  - Counting in 2s soft
    Skip counting supports understanding equal groups (2s, 5s, 10s)
    - Rote counting to 100 hard
      Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
      - One-to-one counting hard
        One-to-one correspondence requires knowing the number name sequence
  - Addition as combining or putting together two hard
    Multiplication as repeated addition requires understanding addition as combining groups
    - How Many in Total? hard
      Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
      - One-to-one counting hard
        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'
Multiplication as repeated addition hard
Expressing array totals as sums of equal addends requires understanding multiplication as repeated addition
- Counting in 2s soft
  Skip counting supports understanding equal groups (2s, 5s, 10s)
  - Rote counting to 100 hard
    Skip counting in 2s, 5s, 10s requires fluent rote counting by ones first
    - One-to-one counting hard
      One-to-one correspondence requires knowing the number name sequence
- Addition as combining or putting together two hard
  Multiplication as repeated addition requires understanding addition as combining groups
  - How Many in Total? hard
    Understanding addition as combining groups requires knowing numbers represent quantities (cardinality)
    - One-to-one counting hard
      Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'

Unlocks2

What Multiplication Means
hardAges 8—9
Rows & Columns in Rectangles
hardAges 7—8