Show:
Base Camp Estimators
Supply Masters: Standard Algorithm + Multiply First, Decimal Second
Expedition Challenges
Final Jeopardy
🏔️ The Great Expedition Challenge
100

Use compatible numbers to estimate:

17.3 × 41.8

17.3 × 41.8

✅ 20 × 40 = 800 (this is the best compatible number and will appear on checkpoint)

✅ 18 × 40 = 720 

100

Find:

14.3 × 0.2

143 × 2 = 286

Count decimal places:

14.3 has 1 decimal place 0.2 has 1 decimal place

✅ Final Answer: 2.86

100

Question

An explorer hikes 4.5 miles on Monday.

Another explorer hikes 1.5 times as many miles.

How many miles did the second explorer hike?

4.5 × 1.5

Ignore decimals:

45 × 15 = 675

Count decimal places:

✅ Answer: 6.75 miles

200

Use rounding to the nearest whole number to estimate:

8.7 × 19.6

✅ 9 × 20 = 180

8.7 rounds to 9.

19.6 rounds to 20.

9 × 20 = 180.

200

Find:

6.7 × 2.3

67 × 23 = 1541

Count decimal places:

✅ Final Answer: 15.41



200

An explorer buys 2.75 pounds of trail mix.

Trail mix costs $3.12 per pound.

How much does the explorer spend?

2.75 × 3.12

Ignore decimals:

275 × 312 = 85800

Count decimal places:

✅ Answer: $8.58

300

Lucas estimated:

57.7 × 3.2 ≈ 180

Question

Explain how Lucas found 180.

✅ Lucas rounded:

57.7 → 60

3.2 → 3

60 × 3 = 180

300

Find:

2.16 × 0.57

216 × 57 = 12312

Count decimal places:

✅ Final Answer: 1.2312

300

An explorer earns $6.80 per hour working at Base Camp.

The explorer works 6.5 hours.

How much money does the explorer earn?

6.80 × 6.5

Ignore decimals:

680 × 65 = 44200

Count decimal places:

✅ Answer: $44.20

300

An explorer is preparing supplies for a mountain expedition.

The explorer buys:

  • 2.75 pounds of trail mix at $3.12 per pound
  • 3.5 pounds of almonds at $11.50 per pound

Questions

  1. How much did the trail mix cost?
  2. How much did the almonds cost?
  3. How much money was spent altogether?

Step 1: Find the cost of the trail mix.

2.75 × 3.12 = 8.58

The trail mix cost $8.58.

Step 2: Find the cost of the almonds.

3.5 × 11.50 = 40.25

The almonds cost $40.25.

Step 3: Find the total money spent.

8.58 + 40.25 = 48.83

The explorer spent $48.83 altogether.