Rows that help us count
Find totals in rectangular arrays with up to five rows and five columns.
Explore this lesson →8 practice questions · Optional read aloud · Thinking pad
Let’s understand the idea.
- A row goes across; a column goes down. A complete rectangular array has the same count in each row.
- Count one whole row and add that amount for every row. Or count one column and add that amount for every column.
- Count each object once. Both directions give the same total.
Something to notice
Ask the learner to pair a new collection, explain odd/even without relying only on the final digit, arrange their own rectangle and connect each addend to a complete row or column. The supplied diagrams scaffold this reasoning; correct entries alone do not establish independent modeling or fluent recall.
Try it. Change it. Explain it.
Open the lesson to use its pictures and controls. In How it works, connect the picture to the idea. In Play & discover, change the quantities and notice what stays the same. In Your turn, answer questions and use the explanation to check your reasoning.
You can ask for help, draw on the thinking pad, or listen to the question and answer options. Progress distinguishes independent work from work completed with help.
Let’s try it →Curriculum connection
Grade 2 · 2.OA · US Common Core
This lesson is mapped to these standards. A completed activity is practice evidence, not a claim of mastery. Content is checked against the linked official standards and its mathematical models are tested.