Explorer · core practice • Add/Subtract Within 100 • 2nd Grade • Bakery scenario

Bakery Order Tally: 2nd Grade Add/Subtract Within 100 Practice

Welcome to "Bakery Order Tally", a Grade 2 Add and Subtract within 100 mission at the Explorer core practice level, staged in a bakery scenario. The mission opens with a hands-on prompt: "We will add 47 and 28. First, model the tens of 28: build 2 trays of 10 pastries." Students work with the numbers 47, 28, 2 and reach a final answer of 47 across 3 guided steps.

Behind the story, this lesson builds add and subtract within 100 understanding aligned to CCSS 2.NBT.B.5. The key strategy is: 47 + 28 = 75.

A common misconception this page surfaces is: Adding tens onto ones (e.g. 23 + 4 = 63). Line up columns. 4 ones never stack onto the tens column — only ones onto ones. The adaptive Socratic hints move from a small nudge to a fuller strategy, keeping the reasoning visible for students, parents, and teachers.

Grade 2 · Add and Subtract within 100

Bakery Order Tally

Mission Progress

0/3

Thinking Summary · 1

Mastered

Visual Logic: 0 groups of 0.

[Discovery] We will add 47 and 28. First, model the tens of 28: build 2 trays of 10 pastries.

1

Active Step

[Discovery] We will add 47 and 28. First, model the tens of 28: build 2 trays of 10 pastries.

Sharing Lab

Distribute items equally among groups

Tap "+ Add Group" to start distributing.
Groups0 / 2
Items / Group0 / 10
Explorer core practice

What students practice on this page

2nd Grade Add/Subtract Within 100 explorer-1 representative practice page for students who need a crawlable, worked entry point into the topic without exposing every near-duplicate long-tail mission.

  • Practice add/subtract within 100 through a equal-groups model before writing the final answer.
  • Move across 3 Socratic steps: notice the situation, connect the model, then check the symbolic answer.
  • Use this explorer-1 representative mission as the indexable entry point for the wider 2nd Grade Add/Subtract Within 100 sequence.
Worked Practice Guide

How to solve Bakery Order Tally

This explorer · core practice mission uses a equal-groups model to move from the story to a precise add/subtract within 100 idea. Work through the prompts in order: notice the structure first, name the quantities, then check whether the final answer fits the original situation.

1 Discovery equal-groups model

We will add 47 and 28. First, model the tens of 28: build 2 trays of 10 pastries.

Expected reasoning
2 groups of 10, total 20
Teacher hint
Make 2 trays, each with 10 pastries.

Common wrong turn: 28 is the WHOLE addend. The tens portion is 20.

2 Abstraction number sentence

Compute: 47 + 28 = ?

Expected reasoning
75
Teacher hint
47 + 28 = 75.

Common wrong turn: Wrong operation — the prompt says "add".

3 Reflect number sentence

If 47 + 28 = 75, then 75 − 28 = ?

Expected reasoning
47
Teacher hint
Inverse of "+ 28" is "− 28". So the answer is 47.

Common wrong turn: 28 is the addend you SUBTRACT, not the answer.

Why this mission matters

In 2nd Grade Add/Subtract Within 100, students need to connect the story, the model, and the symbolic answer. The core move here is: 47 + 28 = 75. A useful check is to ask whether the answer avoids this pitfall: Adding tens onto ones (e.g. 23 + 4 = 63). Line up columns. 4 ones never stack onto the tens column — only ones onto ones.

How to start and what to do next

  • Use this representative page when the student understands the model and needs grade-level abstraction.
  • If the student cannot explain the equal-groups model, use the topic guide before assigning more missions.
  • If the equal-groups model is clear, ask the student to restate the same idea with the number sentence.
Related concept path

Continue from this representative mission

No long-tail expansion
Extra practice without extra index bloat

Try these variations after the mission

  • Change the key number set from 47, 28, 2 to 48, 29, 3 and solve the same structure again.
  • Write a new question where 47 is still the final answer, then explain which quantities changed and which stayed fixed.
  • Ask the student to explain the first step without calculating first; the goal is to name the equal-groups model before using a rule.