1. Holt CA Course 1 4-1 Estimating with Fractions Prep for NS2.1 Solve problems involving addition, subtraction, multiplication, and division of positive fractions and explain why a particular operation was used for a given situation. California Standards

2. Holt CA Course 1 4-1 Estimating with Fractions Sometimes, when solving problems, you may not need an exact answer. To estimate sums and differences of fractions and mixed numbers, round each fraction to 0,, or 1. You can use a number line to help. 1212 1212 0 1 3 10 is closer to than to 0. 1212 3 10

3. Holt CA Course 1 4-1 Estimating with Fractions You can also round fractions by comparing its numerators with its denominators.

4. Holt CA Course 1 4-1 Estimating with Fractions Teacher Example 1: Measurement Application A blue whale can grow to 33 m long, while 3535 the great white shark may be as long as 4 m. 1212 Estimate how much longer the blue whale is than the great white shark. 33 3535 – 4 1212 3535 1212 4 1212 4 1212 Round each mixed number. Subtract. The blue whale is about 29 m longer. = 29– 33 1212 4 1212

5. Holt CA Course 1 4-1 Estimating with Fractions Student Practice 1: 11 1212 – 2 7878 1212 1212 2 7878 3 Round each mixed number. Subtract. = 8 – 11 1212 3 1212 A Cocker Spaniel may grow to weigh about 11 kilograms while the Chihuahua may weigh about 2 kilograms. Estimate how much more the Cocker Spaniel weighs than the Chihuahua. 7878 1212 The Cocker Spaniel weighs about 8 kg more. 1212

6. Holt CA Course 1 4-1 Estimating with Fractions Estimate each sum or difference. Teacher Example 2A & 2B: Estimating Sums and Differences A. 7979 – 2525 1 2525 1212 1 – = 7979 Round each fraction. Add. 5959 B. 4 + 3 1818 4 5959 4 1212 3 1818 3 Round each mixed fraction. Subtract. 4 1212 + 3 = 7 1212 1212 1212

7. Holt CA Course 1 4-1 Estimating with Fractions Estimate the difference. Teacher Example 2C: Estimating Sums and Differences Subtract. 1818 C. 2 – 1 12 2 1818 2 Round each number. 1 12 0 2 – 0 = 2

8. Holt CA Course 1 4-1 Estimating with Fractions Estimate each sum or difference. Student Practice 2A & 2B: A. 7878 – 1616 1 1616 0 1 – 0 = 1 7878 Round each fraction. Add. 3535 B. 5 + 2 2929 5 3535 5 1212 2 2929 2 Round each mixed fraction. Subtract. 5 1212 + 2 = 7 1212

9. Holt CA Course 1 4-1 Estimating with Fractions Estimate the difference. Student Practice 2C: Subtract. 2929 C. 4 – 8 15 4 2929 4 Round each number. 8 15 1212 1212 – = 3 1212 4

10. Holt CA Course 1 4-1 Estimating with Fractions You can estimate products and quotients of mixed numbers by rounding to the nearest whole number. If the fraction in a mixed number is greater than or equal to, round the mixed number up to the next whole number. If the fraction is less than, round down to a whole number by dropping the fraction. 1212 1212

11. Holt CA Course 1 4-1 Estimating with Fractions Teacher Example 3A: Estimating Products and Quotients Estimate each product or quotient. 3 7 = 21 Multiply. 2929 3 6 5656 3 2929 3 6 5656 7 Round each mixed number to the nearest whole number.

12. Holt CA Course 1 4-1 Estimating with Fractions Teacher Example 3B: Estimating Products and Quotients Estimate each product or quotient. 14 ÷ 2 = 7 Divide. 4545 13 ÷ 2 1414 13 4545 14 2 1414 2 Round each mixed number to the nearest whole number.

13. Holt CA Course 1 4-1 Estimating with Fractions Student Practice 3A: Estimate each product or quotient. 8 3 = 24 Multiply. 2323 7 2 3434 7 2323 8 2 3434 3 Round each mixed number to the nearest whole number.

14. Holt CA Course 1 4-1 Estimating with Fractions Student Practice 3B: Estimate each product or quotient. 12 ÷ 3 = 4 Divide. 7878 11 ÷ 3 1313 11 7878 12 3 1313 3 Round each mixed number to the nearest whole number.