Grade 2 Addition and subtraction within 1000: Free Course

About this course

Hundreds, tens and ones provide a structure for three-digit arithmetic. This Grade 2 course uses place-value blocks, decomposition and mental strategies for calculations within 1000. Study the complete public source playlist from Khan Academy in English, with all 11 recordings in the on-site classroom. Original lesson titles, source order and repeated entries are preserved.

Course at a glance

What you’ll learn

• Decompose three-digit numbers into hundreds, tens and ones.
• Add and subtract three-digit quantities.
• Explain regrouping with place-value blocks.
• Use mental strategies and number lines to check arithmetic.

Skills you’ll gain

• Three-digit arithmetic
• Place-value blocks
• Mental calculation
• Regrouping

Course Overview

Adding or subtracting ten and one hundred highlights which place changes. Breaking apart three-digit numbers then connects mental arithmetic with a written calculation. Examples without regrouping establish the basic structure before a place-value-block subtraction demonstrates exchanging one unit of a larger place for smaller units. Number lines provide another representation of the same changes. The goal is to understand why a method works and to keep each place aligned, rather than memorizing a column procedure detached from quantity. All demonstrations remain in their original source positions, including examples that revisit the same place-value relationship from another direction.

How to study the course

• Videos 1–2: this part of the source list includes “Subtracting ten or one hundred” through “Breaking apart 3-digit addition problems”. State the quantities and conditions before calculating. Keep a brief working note, revisit an unclear explanation and test one example before moving to another part of the material.
• Videos 3–5: this part of the source list includes “Addition using groups of 10 and 100” through “Adding and subtracting on number line 2”. Keep equivalent expressions or representations connected. Keep a brief working note, revisit an unclear explanation and test one example before moving to another part of the material.
• Videos 6–8: this part of the source list includes “Adding 3-digit numbers (no regrouping)” through “Solving 3-digit addition in your head”. Check each operation with a small example before extending it. Keep a brief working note, revisit an unclear explanation and test one example before moving to another part of the material.
• Videos 9–11: this part of the source list includes “Adding ten or one hundred” through “Subtracting with place value blocks (regrouping)”. Explain a result in words as well as symbols. Keep a brief working note, revisit an unclear explanation and test one example before moving to another part of the material.

Who is this for?

This course suits students, returning learners and anyone strengthening the specific mathematics named in the course. It also provides a recorded reference for revisiting a topic after an earlier lesson or study attempt. Choose examples appropriate to your background and allow time to work through the method instead of judging understanding only by how familiar the terminology sounds.

Before you start

Comfort with the preceding arithmetic or algebra skills is useful. Keep paper, a pencil and a calculator when a lesson uses one. Grade-specific courses assume the learner’s earlier grade-level knowledge.

Put the lessons into practice

Choose a three-digit addition and represent both numbers by place. Combine the parts and compare with a written method. Then model a subtraction that needs an exchange. Explain why the total value stays the same during regrouping, and use the inverse operation to check the answer.

This optional study activity is provided by WikiFree for independent practice. Keep your working notes and use the relevant classroom recording to check a step, definition or interpretation. It is not an instructor-marked assignment.

Certificate / Assessment

Watching the public videos and using WikiFree completion tracking does not award a certificate, academic credit, an examination voucher or instructor assessment. Use your practice output to review what you can explain and repeat independently. The recorded lessons provide study material; completion tracking records your progress through that material.

Frequently asked questions

Provider: Khan Academy. Videos play from the Khan Academy channel on YouTube.