Challenger · stretch problem Comparing 1st Grade Bakery scenario

Donut Size Tester: 1st Grade Comparing Practice

Welcome to "Donut Size Tester", a 1st Grade Comparing mission at the Challenger (stretch) level, staged in our bakery scenario. The mission opens with a hands-on prompt: "A balance has 45 on the LEFT and 54 on the RIGHT. Add weight to the lighter pan until both pans match." You'll work with the numbers 45, 54 and arrive at a final answer of 9 across 3 guided steps.

Behind the bakery story, this lesson is really about comparing aligned to CCSS 1.NBT.B.3. Comparing two-digit numbers using the symbols >, <, and =. The key strategy this mission asks you to internalise: > means greater, < means less, = means equal.

A general pattern to watch for in 1st Grade comparing — illustrated with example numbers below, which may differ from this lesson's: Thinking "equal" means "same shape" instead of "same amount". Show 3 big blocks and 3 small blocks. Both sides = 3. Equal by count, not size. If you get stuck on "Donut Size Tester", the adaptive Socratic hints below escalate from a gentle nudge to a worked-out strategy — the same way a one-on-one tutor would coach you through it.

Grade 1 · Comparing

Donut Size Tester

Mission Progress

0/3

Thinking Summary · 1

Mastered

[object Object]

[Discovery] A balance has 45 on the LEFT and 54 on the RIGHT. Add weight to the lighter pan until both pans match.

1

Active Step

[Discovery] A balance has 45 on the LEFT and 54 on the RIGHT. Add weight to the lighter pan until both pans match.

Balance Scale

Equation: Compare 45 vs 54

+0→ left pan
45
Left
54
Right
Add weight to the left pan until both pans match.
Challenger stretch check

What students practice on this page

1st Grade Comparing challenger-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 comparing through a balance scale before writing the final answer.
  • Move across 3 Socratic steps: notice the situation, connect the model, then check the symbolic answer.
  • Use this challenger-1 representative mission as the indexable entry point for the wider 1st Grade Comparing sequence.
Worked Practice Guide

How to solve Donut Size Tester

This challenger · stretch problem mission uses a balance scale to move from the story to a precise comparing 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 balance scale

A balance has 45 on the LEFT and 54 on the RIGHT. Add weight to the lighter pan until both pans match.

Expected reasoning
mode: compare; p: 45; q: 54; target: 9
Teacher hint
Add 9 to the left pan.
2 Abstraction multiple-choice check

Which symbol belongs between 45 and 54? 45 ? 54

Expected reasoning
answer: <; options: >, <, =
Teacher hint
> means greater, < means less, = means equal.
3 Reflect number sentence

How many must we add to the SMALLER side to make both sides equal?

Expected reasoning
9
Teacher hint
Compare then subtract.

Why this mission matters

In 1st Grade Comparing, students need to connect the story, the model, and the symbolic answer. The core move here is: > means greater, < means less, = means equal. A useful check is to ask whether the answer avoids this pitfall: Mixing up the > and < symbols. The hungry crocodile always eats the bigger number. Mouth = open side.

How to start and what to do next

  • Use this representative page when the student is ready for mixed representations and test-style traps.
  • If the student cannot explain the balance scale, use the topic guide before assigning more missions.
  • If the balance scale is clear, ask the student to restate the same idea with the multiple-choice check.
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 45, 54, 9 to 46, 55, 10 and solve the same structure again.
  • Write a new question where 9 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 balance scale before using a rule.