# Estimating and rounding numbers, Read This

Estimating and rounding numbers, Read This

Can you estimate how tall your friend is? Try to assess the height of the friend sitting next to you! The estimated result is not the actual result. But it is a result that is close to the actual result. The estimated value can be higher or lower than the actual result.

1. Rounding Numbers into the Nearest Fraction Rounding to the nearest tens is done with the following rules.

a. Numbers 0, 1, 2, 3, and 4 (less than 5) are rounded down to 0 or omitted.

b. While unit digits 5 and above (5, 6, 7, 8, and 9) are rounded up to 1 tens.

1.24 is rounded to the nearest tenth to 20.

2. 45 is rounded to the nearest tenth to 50.

3. 58 is rounded to the nearest tenth to 60.

2. Rounding Numbers to the Nearest Hundred Rounding off numbers to the nearest hundreds is carried out with the following rules.

a. Numbers less than 50 are rounded down to 0.

b. Numbers 50 and above are rounded up to 100.

1. 140 is rounded to the nearest hundreds to 100.

2. 548 is rounded to the nearest hundreds to 500.

3. 456 is rounded to the nearest hundreds to 500.

3. Rounding Numbers to the Nearest Thousands Rounding numbers to the nearest thousands is done as follows.

a. Numbers less than 500 are rounded down to 0.

b. Numbers 500 and above are rounded up to 1,000.

1. 4,250 is rounded to the nearest thousand to 4,000.

2. 5,581 is rounded to the nearest thousand to 6,000.

3. 6,769 is rounded to the nearest thousand to 7,000.

4. Estimating the Results of Count Operations There are 3 kinds of estimates in arithmetic operations, namely:

a. High estimate The height estimate is made by rounding up all the numbers to be operated on first.

b. Underestimation Underestimation is done by rounding down all numbers to be operated first.

c. Best approximation A good approximation is made by rounding up all numbers to the nearest tens, hundreds, or thousands first.

Estimate the result of 46 + 52 for:

a. high estimate,

b. low estimate,

a. Estimated height 46 rounds off to 50 52 rounds up to 60 So, estimated height of 46 + 52 = 50 + 60 = 110.

b. Underestimation of 46 is rounded up to 40 52 is rounded up to 50 So, underestimation of 46 + 52 = 40 + 50 = 90.

c. Best estimate of 46 rounds to 50 52 rounds to 50 So, best estimate of 46 + 52 = 50 + 50 = 100.

5. Solving Problems Involving Money In this section, you will learn how to solve problems involving money.

Endah, Iwan, and Ratri went to a restaurant. The price list for food and drinks at the restaurant is:

Food: Drinks:

- Meatballs IDR 5000.00 - Ice tea IDR 1000.00

- Chicken noodles IDR 4,500.00 - Orange ice IDR 1,500.00

- Soto IDR 4,000.00 - Fruit ice IDR 2,000.00

Endah ordered meatballs + iced tea. Iwan ordered chicken noodles + fruit ice. Ratri ordered soup + orange ice. Of the three children, who paid the most?

To answer this question, you need to recall the calculations using money in grade 3. Now you will study the groups of currencies with higher values.