Castles on a number line throw pumpkins at each other: read the target's number in words, find the gap on paper, fix it for the wind and set the dial. Right decimals hit every time. Grade 5.
Math (Decimals)Grades 58 roles55 min1 class period
Math (Decimals)Grades 58 roles55 min1 class period
The county fair pumpkin toss, late afternoon
Castles on a number line throw pumpkins at each other: a group reads its target's number in words, works the gap on paper, fixes it for the wind, picks Lob, Flat or Big lob and sets the dial. If the decimals are right, the pumpkin hits.
Hundredths lands in a grade 5 decimals unit, after students can add and subtract decimals to hundredths, halve a decimal, and have met place value to thousandths. Every round is one chain of decimal work: read a number in words, subtract to find the gap, add or take away the wind, then divide by 2 or 10 and round to the hundredth. Dividing by ten moves every digit one place (5.NBT.A.1, A.2), and a Big lob dial must be rounded, not cut off: cutting it off misses more than half the time (5.NBT.A.4). The game does not cover exponents or powers of ten beyond 10, rounding to other places, number names past hundredths, expanded form, comparing decimals as a skill, multiplying or dividing decimals by decimals, or the whole-number algorithms of 5.NBT.B.5 and B.6. It suits grade 5 math teachers, and grade 6 teachers who want a decimal fluency day with a written method.
What Students Will Learn
Read a decimal to the hundredths written in words and write it in digits.
Find the distance between two decimals on a number line by subtracting the smaller from the larger.
Add or subtract a decimal wind correction before scaling a throw.
Divide a hundredths number by 2 or by 10 and round the result to the hundredth.
Explain why each digit shifts one place when a number is multiplied or divided by 10.
Cases Included
CCSS.MATH.CONTENT.5.NBT.B.7 - add and subtract decimals to hundredths, and relate the work to a written method
CCSS.MATH.CONTENT.5.NBT.A.2 - divide a decimal by 10 and explain where the decimal point goes
CCSS.MATH.CONTENT.5.NBT.A.3.a - read decimals to hundredths written as number names
CCSS.MATH.CONTENT.5.NBT.A.4 - round decimals from thousandths to hundredths
CCSS.MATH.CONTENT.5.NBT.A.1 - a digit in one place is worth 10 times the place to its right
CCSS.MATH.PRACTICE.MP6 - attend to precision
Social & Emotional Learning (CASEL)
Aligned to the CASEL framework's core competencies. These are the SEL skills students actively practice while playing.
Responsible Decision-MakingEach group commits a computed throw and picks the lever before it sees any result.
Self-ManagementA miss happens in front of the room, and the next round is a fresh start.
Flexible Class Sizes
4 castles
Up to 12 students, groups of 3. Untick a castle for a very small class.
5 castles
13 to 20 students, groups of 3 or 4.
6 castles
21 to 24 students, groups of 4. The best fit for the period.
7 castles
25 to 28 students, groups of 4.
8 castles
29 to 32 students. The period is tight: end after round 4 if you need to.
How the Game Plays Out
Roles Your Students Will Play
8 teams. The teacher assigns students to teams when the game starts.
Castle Oak
Castle Birch
Castle Maple
Castle Cedar
Castle Willow
Castle Pine
Castle Elm
Castle Spruce
Hand Each Student Their Own Sheet
One click on the teacher dashboard prints a dossier for every role - background, goals, key facts, and their confidential briefing - plus the primary-source packet and a vocabulary sheet. Print them, or save as PDF, so each student reads their role on paper instead of huddling around one screen. The app still runs the votes and the action; the paper just carries the reading.
Primary Sources
Every role includes real historical documents. Students read them because they need the information to make their case.