Rounding Radar

Cadet Taylor was asked to round 4.348 to the nearest tenth. Taylor wrote:

"4.348 rounds to 4.35, and then 4.35 rounds to 4.4!"

What is Taylor's misconception?

Correct Rounded Value (Tenth):

Glitch Case Bravo Cadet Error

Cadet Jordan was asked to round 8.97 to the nearest tenth. Jordan wrote:

"8.97 rounds to 9."

Why is "9" technically incomplete for tenths precision?

Correct Written Form (with tenths precision):

4 Part 4: Mission Telemetry Flight Operations (Word Problems)

Show thinking with benchmarks or number lines

Mission Alpha: Drone Payload

A high-altitude reconnaissance drone records a fuel payload mass of 18.645 kilograms.

a) Round fuel mass to nearest hundredth:

b) Round fuel mass to nearest tenth:

c) Show work / justification space:

Mission Bravo: Satellite Orbit

Ground tracking radar monitors a low-orbit satellite traveling at an altitude of 142.508 miles above Earth.

a) Round orbital altitude to nearest whole mile:

b) Round orbital altitude to nearest hundredth:

c) Show work / justification space:

Part 5: Radar Command Mystery Challenge (Reverse Reasoning)

Brain Stretcher

A stealth aircraft's telemetry code has three decimal places.

• When rounded to the nearest tenth, it rounds to 7.4.
• When rounded to the nearest hundredth, it rounds to 7.38.

Identify one possible 3-decimal number:

Explain your reasoning:

Rounding Radar • Telemetry Practice • NY-5.NBT.4 Scoring: _____ / 20 Points Page 2 of 2

*Teacher Note on 12.951 to tenths: Ensure students write 13.0 (not 13) to demonstrate precision to the tenths place.

Rounding Radar • Answer Key • NY-5.NBT.4 Solutions for Parts 3, 4, 5 & Exit Ticket on Page 2 → Page 1 of 2

Rounding Radar • Applied Solutions & Exit Ticket Key

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3 Part 3: Glitch Detective Solutions (2 pts each • 4 pts total)

Glitch Case Alpha (Taylor: 4.348 → 4.4)

Misconception: Sequential / domino rounding. Taylor looked at the thousandths digit (8) to round hundredths to 5, then rounded tenths up. You must look only at the benchmarks 4.3 and 4.4. Midpoint is 4.350; 4.348 is less than 4.350.

Correct Answer: 4.3

Glitch Case Bravo (Jordan: 8.97 → 9)

Misconception: Omitting precision indicator. Writing "9" indicates rounding to whole numbers. Rounding to the nearest tenth requires reporting a digit in the tenths place.

Correct Answer: 9.0 (preserves tenths precision)

Part 4: Mission Operations (1 pt per sub-item)

Mission Alpha (Drone 18.645 kg):

a) Nearest hundredth: 18.65 kg (midpoint is 18.645, rounds up!)

b) Nearest tenth: 18.6 kg (18.645 is below 18.650)

Mission Bravo (Satellite 142.508 mi):

a) Nearest whole: 143 miles (midpoint is 142.500, 142.508 > 142.500)

b) Nearest hundredth: 142.51 miles (midpoint is 142.505)

Part 5: Command Challenge (2 pts)

Number has 3 decimal places. Rounds to 7.4 (tenths) and 7.38 (hundredths).

Possible Solutions: 7.375, 7.376, 7.377, 7.378, 7.379, 7.380, 7.381, 7.382, 7.383, 7.384.

Reasoning: To round to 7.38 in hundredths, the number must be between 7.375 and 7.384. Any of these values also rounds to 7.4 in tenths because they are all \(\ge 7.35\).

Exit Ticket Answer Key & 4-Point Rubric

Total: 4 Points

Item 1: 5.48 to Tenths (1 pt)

Upper: 5.5 | Lower: 5.4
Midpoint: 5.45
Point: 5.48 is above midpoint.
Answer: 5.5

Item 2: 13.962 Dual Check (1 pt)

a) Hundredths: 13.96
(between 13.96 & 13.97; midpoint 13.965)
b) Nearest Whole: 14
(between 13 & 14; 13.962 > 13.5)

Item 3: True / False & Explain (2 pts)

FALSE (1 pt)
Explanation (1 pt): Rounding to tenths compares 0.849 directly to 0.8 and 0.9. The midpoint is 0.850. Because 0.849 < 0.850, it rounds to 0.8. Sequential rounding is incorrect.

Score 0–2 Points:

Re-teach with vertical meter stick & benchmark highlights tomorrow.

Score 3 Points:

Minor precision slips (e.g. trailing zeros); assign Quick Warmup Check.

Score 4 Points:

Mastery confirmed; advance to multi-step decimal estimation.

Rounding Radar • Answer Key & Rubrics • NY-5.NBT.4 Classroom Ready Page 2 of 2