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- Estimation

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Get Started Now- Intro Lesson: a11:42
- Intro Lesson: b8:42
- Intro Lesson: c14:30
- Intro Lesson: d14:41
- Intro Lesson: e5:47
- Intro Lesson: f8:17
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- Lesson: 5d2:18
- Lesson: 6a6:14
- Lesson: 6b7:45

In this lesson, we will learn:

- How to estimate the answer to division statements
- The three methods for estimating quotients: estimation by rounding, estimation with compatible numbers, estimation with long division
- How to check and compare your estimated quotients with the exact answer

- An
**estimation**is a rough calculation of what the**exact answer**could be around. It is less exact but easier (faster) to calculate! - When
**estimating**, it is helpful to remember the rules for**rounding**numbers: - If the number to the right of the digit you are rounding to is $\geq$ 5, round UP; if the number is < 5, round DOWN
- For mixed fractions, round to the nearest whole number: if the fraction part is $\geq$ $\frac{1}{2}$, round UP. If the fraction part is < $\frac{1}{2}$, round OWN.
- Three methods to estimate
**quotients**are:**estimation by rounding, estimation with compatible numbers**, and**estimation with long division**. **Estimation by Rounding:**
1. - Round each number to its greatest place value
- For mixed fractions, round to the nearest whole number
- If there are more place values in the dividend compared to the divisor, you can try rounding smaller place values to have more precise estimates
**Estimation with Compatible Numbers:**
1. Use - Think of numbers that are close to the dividend and divisor that are “compatible” (easier to compute using your times tables)
- If dividing mixed fractions, remember to convert back into
**improper fractions**first - Then, change the division to multiplication by flipping the second fraction (multiplying the
**reciprocal**) **Estimation with Long Division:**
1. Line up the - Write the decimal point in the quotient (answer on top of the long division bracket)
- When is the first time you will write a number in your answer (quotient)?
- Where you can you first start dividing the dividend by the divisor?
- You can
**compare**the**exact quotient**and the**estimated quotient**to see how close they are - For the
: rounding DOWN the dividend will give an__dividend__**underestimate** - Rounding UP the dividend will give an
**overestimate** - For the
: rounding DOWN the divisor will give an__divisor__**overestimate** - Rounding UP the divisor will give an
**underestimate**

- IntroductionIntroduction to Estimating Quotients:a)Example of estimating the quotient of 386 ÷ 22b)Key terms for estimating quotientsc)Estimating quotients by roundingd)Estimating quotients using compatible numberse)Estimating quotients with long divisionf)Underestimating and overestimating quotients
- 1.
**Estimating Quotients by Rounding**

Estimate the quotient using estimation by rounding. Then, find the exact quotient to check your answer.a)54$\frac{2}{5}$ ÷ 5$\frac{4}{6}$ =b)4658 ÷ 17 =c)27.83 ÷ 11 = - 2.
**Estimating Quotients using Compatible Numbers**

Estimate the quotient by rewriting the statement using compatible numbers. Then, find the exact quotient to check your answer.a)3456 ÷ 5 =b)50 ÷ 4$\frac{1}{8}$ =c)5.592 ÷ 6 = - 3.
**Estimating Quotients with Long Division**

Estimate the quotient using estimation with long division. Then, find the exact quotient to check your answer.a)0.672 ÷ 3 =b)4.265 ÷ 5 =c)16.849 ÷ 83 = - 4.
**Estimating Quotients Word Problem - 1**

At a local pie eating contest, the winner ate 13.136 pounds of apple pie in 8 minutes. About how many pounds did the winner eat in one minute?a)Write out the division statement that represents this problem.b)Use estimation by rounding.c)Use estimation with compatible numbers.d)Use estimation with long division. - 5.
**Estimating Quotients Word Problem - 2**

If Laura makes a salary of $41,004 in a year from her job as a laboratory technician, about how much money does she make in 3 months?a)Write out the division statement that represents this problem.b)Use estimation by rounding to estimate the quotient.c)Use estimation with compatible numbers to estimate the quotient.d)Use estimation with long division to estimate the quotient. - 6.
**Estimating Quotients Word Problem - 3**

Trisha was able to complete 28$\frac{1}{3}$ levels in her video game in 3$\frac{1}{5}$ hours.a)About how many levels does she complete each hour? Use multiple estimation methods.b)If Jake finished 71.8 levels of the same game in 9.5 hours, who completed the levels faster? Use multiple estimation methods.