Subtracting Decimals: Calculating Change from $10 at the Farmer's Market

Problem Setup

• 🎯 Omar starts with $10.00 to spend at the farmer's market.
• 🍎 He spends $8.79 on fruit.
• ❓ The goal is to determine how much money Omar has left.

Decimal Subtraction Process

• 💰 To find the remaining amount, we need to subtract $8.79 from $10.00.
• 🔢 When setting up the subtraction, it's crucial to align the place values correctly, ensuring the decimal points are in line.
• ⚠️ Direct subtraction from the hundredths place (0 - 9) is not possible, requiring regrouping (borrowing).

Regrouping and Calculation

• 🏦 We regroup from the tens place, then the ones place, to make the subtraction possible.
• ➡️ This process involves converting units: a ten becomes ten ones, and a one becomes ten tenths, and a tenth becomes ten hundredths.
• ✅ The subtraction yields: 100ths place: 10 - 9 = 1; 10ths place: 9 - 7 = 2; 1s place: 9 - 8 = 1.

Final Result and Verification

• 💸 Omar has $1.21 left.
• 📊 Image C correctly represents $1.21, showing one dollar, two dimes (20 cents), and one penny (1 cent).