Estimation is the process of making a close guess about a number, quantity, or measurement without counting or calculating exactly. It helps us quickly find an approximate answer that is “good enough” for many real-life situations.

Examples:

1. If you have 23 apples and 19 oranges, you might estimate that you have about 20 apples and 20 oranges, so around 40 pieces of fruit in total.
2. You have 52 marbles, and your friend has 46 marbles. You estimate that together you have about 50 + 50 = 100 marbles.
3. There are 29 students in one class and 33 students in another. You estimate that there are about 30 + 30 = 60 students in total.
4. You see a jar of 78 jellybeans. You estimate that there are about 80 jellybeans in the jar.

Rounding is a math technique used to simplify numbers by adjusting them to the nearest ten, hundred, thousand, or other place value. It helps make calculations quicker and easier, especially for mental math and estimation.

How to Round Numbers

Rounding Rule:

1. Identify the rounding digit (the place you’re rounding to—tens, hundreds, etc.).
2. Look at the digit to the right of the rounding digit.
   • If it’s 5 or higher → Round up (+1 to the rounding digit).
   • If it’s 4 or lower → Keep the rounding digit the same.
3. Replace all digits to the right with zeros (if needed).

Examples of Rounding to the Nearest Ten:

Number	Look at Ones Digit	Rounded to Nearest Ten
34	4 (less than 5) → Round down	30
87	7 (5 or higher) → Round up	90
65	5 (5 or higher) → Round up	70

Examples of Rounding to the Nearest Hundred:

Number	Look at Tens Digit	Rounded to Nearest Hundred
142	4 (less than 5) → Round down	100
378	7 (5 or higher) → Round up	400
950	5 (5 or higher) → Round up	1000

More Rounding Examples:

1. Example 1:
   57 rounded to the nearest ten is 60 (because the digit in the ones place is 7).
2. Example 2:
   84 rounded to the nearest ten is 80 (because the digit in the ones place is 4).
3. Example 3:
   13 rounded to the nearest ten is 10 (because the digit in the ones place is 3).
4. Example 4:
   29 rounded to the nearest ten is 30 (because the digit in the ones place is 9).
5. Example 5:
   91 rounded to the nearest ten is 90 (because the digit in the ones place is 1).

Estimation is a powerful math shortcut that helps us make quick, practical decisions. Whether you’re shopping, traveling, or solving math problems, being able to estimate saves time. Practice rounding numbers you see daily—prices, ages, or even the number of steps you take! The more you practice, the faster and more accurate you’ll become.