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MASTERITRAIL / ELEMENTARY · GRADES 3–5

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Learn first or practice in Number Depot

Start with Learn in the unit below, or go straight to the three-checkpoint mission for practice with help.

Start learning · Practice in Number Depot · Extra 100,000 lesson (sign-in required)

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Guest work lasts only for this visit. Authorized signed-in learners can retain mission and learning-check evidence; check the private progress panel for save status. Learn, guided practice, independent practice, self-review and reflection are temporary page work. The three linked lessons use separate Save draft and Complete lesson buttons for ungraded typed responses. Paper drawings and spoken explanations are not recorded.

Explore this unit in three lessons

Read, investigate, and write in two activities per lesson. Signed-in learners can save ungraded responses separately from the original unit activities below.

  1. Build and exchange place-value parts
  2. Compare a depot ledger
  3. Round with endpoints and a reason

Teacher tools: Private pacing · Completed lesson responses

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MasteriTrail Discover together← Grade 3 pathway

Grade 3 · Mathematics · Unit 1 of 6

Number Sense & Place Value

How does a digit’s position help us build, compare, and estimate a number?

0 of 5 learning steps explored

Lesson steps, guided practice, written responses, and reflections stay in this page session. Copy unrestricted responses or download protected responses before leaving. No name is needed for guest practice.

Make it. Move it. Tell it.

Number Depot: build a paper shipment

I can build a big number. I can show which number is greater. I can find the nearest hundred.

Off-screen quest

Try this with a grown-up, in class, or on your own when safe. You can also use the lesson below. This quest is your choice.

Open off-screen quest + Parent Guide

Your quest

Get ready

  • Get paper and a pencil. No blocks are needed.
Words and source clues
Place value
A digit’s place tells what it is worth.
Expanded form
Add the value of each place.
Expanded notation
Multiply each digit by its place value. Then add.
Round
Use a nearby number. Today, find the nearest hundred.

Screen burst: 15:0015 minutes max

Your guide is getting ready.

Paper quest steps

  1. Screen burst 1

    Your depot needs a new label! Look at 31,407. Read the place names with a grown-up. Then take the quest to paper.

  2. Offscreen: build

    Write 31,407 above your chart. Put each digit in its place. Draw marks to show each group. Leave the tens place empty. Write 0 there. Tell what each group is worth. Write the parts as a sum. Then write each digit × its place value.

  3. Offscreen: compare

    Write 31,047 on a new row. Look from left to right. Stop at the first place that differs. Which number is greater? Name that place. Use < or > to show your answer.

  4. Offscreen: round

    Draw a line from 31,400 to 31,500. Mark 31,450 in the middle. Put 31,407 on the line. Which end is closer? Write “about” before your rounded number.

  5. Screen burst 2

    Show your paper work. Tell why the zero matters. Then try one Number Depot step. Use your chart if you need help. You may stop and come back to the paper quest.

Use your paper chart. Build 31,407. Compare it with 31,047. Draw the line from 31,400 to 31,500. Tell a grown-up what you found.

Grown-up note: Supported practice is not an independent assessment. This guide is not shown during mission play, independent practice, or the learning check. The timer is a reminder for this guide, not a device-wide limit. It stops new guide steps, not the rest of the lesson, and never saves, submits, or grades work. Only an anonymous timer deadline is kept in this tab’s session storage; no answers, notes, or account IDs. If storage is blocked, the reminder lasts only in this open page. A grown-up can use a separate timer too. After a real off-screen break, choose a new burst when ready.

Build a number, then defend its size

Your learning mission / Tu misión de aprendizaje

Build a number, then defend its size

LO · Learning Objective / Objetivo

By the end, I can… Represent numbers through 100,000 using place-value parts. Compare whole numbers by the first different place. Use neighboring hundreds to round and explain an estimate.

Essential Question / Pregunta esencial

How does a digit’s position help us build, compare, and estimate a number?

Success Criteria / Criterios de éxito

  • Correct expansion with the empty tens place preserved
  • Correct comparison symbol
  • Reasoning names the first differing place

Skills & Standards / Habilidades y estándares

3.2A · Compose and decompose whole numbers through 100,000, including expanded notation. · 3.2B · Explore ten-to-one exchanges, including ten 10,000 cards for 100,000 in the linked lesson. · 3.2C · This unit practices nearest-hundred rounding on number lines; other intervals in 3.2C are not taught here. · 3.2D · Compare and order whole numbers through 100,000 using comparison symbols.

DOL · Demonstration of Learning / Demostración

Use place value, rather than the number of visible nonzero digits, to restore the depot. Build the label 32,406. Use standard place-value digits: no more than 9 pieces of each kind. Arrange shipment counts from least to greatest. A label reads 18,275. Which estimate to the nearest hundred belongs on its cart? Compare 31,407 with 31,047. Write an expanded form and identify the first place that proves your comparison. Separate learning check: 4 of 5 correct (80% target).

Our base-ten system groups ten ones into one ten, ten tens into one hundred, and ten hundreds into one thousand. A zero keeps an empty place visible. In 24,306, the 3 represents 300, not 3. Expanded form adds its place values: 20,000 + 4,000 + 300 + 0 + 6. Expanded notation shows each digit times its place value: (2 × 10,000) + (4 × 1,000) + (3 × 100) + (0 × 10) + (6 × 1). Both equal 24,306. Zero terms may be left out of either sum, but the numeral still needs its zero.

The Number Depot build uses five places, from ones through ten thousands, with at most nine pieces per place. Its largest possible label is 99,999. In the linked Build and exchange place-value parts lesson, ten 10,000 cards trade for one 100,000 card. That exchange uses a sixth place; it is not another piece to find in this mission.

To compare, start at the largest place and move right until the digits differ. For rounding to hundreds, find the hundred below and above the number. The midpoint is 50 after the lower hundred. Choose the closer endpoint; at the midpoint, choose the higher one.

Which delivery is larger: 24,306 or 24,360?

  1. 1

    Both numbers have 2 ten thousands, 4 thousands, and 3 hundreds.

  2. 2

    Compare tens: 0 tens is less than 6 tens. Therefore 24,306 < 24,360.

  3. 3

    24,306 is between 24,300 and 24,400. It is 6 from 24,300 and 94 from 24,400.

24,360 is larger. Rounded to the nearest hundred, 24,306 is 24,300.

Words that help

Place value
Two identical beads occupy different columns; a ten-unit rod sits below the left column and one cube below the right.
Place value depends on position. In this model, the left column represents tens and the right column ones: one bead in the tens column represents ten, while one bead in the ones column represents one. Likewise, the digit 1 has different values in 10 and 1.
View full-size image / Ver imagen completa
The value a digit has because of its position.
Expanded notation
41,205 by place
PlaceDigit × unitAmount
Ten thousands4 × 10,00040,000
Thousands1 × 1,0001,000
Hundreds2 × 100200
Tens0 × 100
Ones5 × 15
41,205: expanded notation is (4 × 10,000) + (1 × 1,000) + (2 × 100) + (0 × 10) + (5 × 1). Expanded form is 40,000 + 1,000 + 200 + 0 + 5. Both equal 41,205.
View full-size 41,205 place-value diagram (opens in a new tab)
Add digit × place-value terms. Expanded form adds the resulting place values; both name the same number.
Round
A marker lies near the right endpoint of a path divided into ten equal units.
Rounding names a nearby multiple of a chosen place value. If the path runs from 0 at the left endpoint to 10 at the right, the marker at 8 is nearer 10, so 8 rounds to 10 to the nearest ten.
View full-size image / Ver imagen completa
Name a nearby multiple of a chosen place value.
Standards connections and official sources

These focused activities address the listed expectations. Completing a unit is practice evidence, not certification of mastery or full-year standards coverage.

Grade 3 · Number Depot: place-value sample · Public sample

Try a sample quiz or sample test

The quiz has 5 questions; the longer test has 10 different questions. Both show your own sample report and skill analysis when complete. These are selected-topic practice samples, not a full unit, course or readiness test.

Temporary for everyone, including signed-in visitors. No name, student record or grade is saved. Leaving or refreshing clears this work. These public demonstration questions and answers are not a secure graded assessment. No timer; no AI grading.