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@ 638d2a79:f5645f4e
2025-02-05 18:05:19When doing division with two-digit dividends, round up to the nearest tens place if the number ends in 6-9.
Example:
200÷29200 \div 29200÷29 can be approximated as 200÷30200 \div 30200÷30, which simplifies to 20÷320 \div 320÷3.Also, zeros cancel out in division.
Example:
20000÷70020000 \div 70020000÷700 can be simplified to 200÷7200 \div 7200÷7, which gives the same answer.Multiplication Rule:
When doing multiplication, do not write out all of the zeros.
Example:
For 90×290 \times 290×2, you don’t need to write out “00” at the start. Just do 9×29 \times 29×2 and add the zero later.Division with Two-Digit Divisors:
If the second digit of the divisor is between 1-5, only divide the first digit by the first digit.
Example:
5124÷215124 \div 215124÷21 can be solved as follows:- Approximate: 5÷2=25 \div 2 = 25÷2=2 (write 2 as the first digit).
- 21×2=4221 \times 2 = 4221×2=42, subtract to get 92.
- 9÷2≈49 \div 2 \approx 49÷2≈4, so 21×4=8421 \times 4 = 8421×4=84, subtract to get 8.
- Bring down the 4 to make 84, which we already know is 21×421 \times 421×4.
- Final answer: 244.
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Converting a Remainder into a Decimal:
To turn a remainder into a decimal, divide the remainder by the divisor.
- Add a zero to the end of your remainder and divide normally.
- The quotient becomes the decimal value.
Example:
32÷10032 \div 10032÷100 → Rewrite as 320÷100320 \div 100320÷100.- 100 goes into 320 three times (3).
- Bring down a zero → 30.
- Add another zero → 300 → 100 goes in three times (3).
- Final answer: 0.32.
If one of the numbers is smaller, like in 880÷22880 \div 22880÷22, where 22 doesn’t go into 0:
- Instead, check how many times 0.22 goes into 88. The answer is 4.
- 22 goes into 0, 0 times.
- So, 880÷22=40880 \div 22 = 40880÷22=40.
Division with Three-Digit Numbers:
Use the same method as with two-digit divisors.
Example: 100,492÷518100,492 \div 518100,492÷518
- Approximate using 5 for each digit of the answer.
Another example:
36.85÷21636.85 \div 21636.85÷216- 222 goes into 3 once → Write 1.
- 216×1=216216 \times 1 = 216216×1=216, subtract from 368 → 152.
- Bring down the 5 and continue dividing.
Calculating Volume:
To find the volume of something, use the equation:
Width×Height\text{Width} \times \text{Height}Width×Height
The answer will be in square units.Example:
A 2D box with width 1 inch and height 4 inches has an area of 4 inches squared.[[America|American]] Flag Instructions:
- The length of the flag is 1.9 times its width.
- Each stripe should be one-thirteenth of the flag's height.
- The blue area covers 7.6 of the flag’s width.
- The height of the blue area is exactly 7 stripes, or 7/13 of the flag’s height.
Finding the Median Score of a Class:
- Count the number of students with the highest score, then move downward.
- Write scores in one column and the number of students in another.
- Find the median of the possible scores.
Example:
Possible scores: 10, 9, 8, 6, 4 → Median is 8.
Then, count students until you reach the middle score (8 or the median value)| Posable score | number of students | | - | | | 10 | 3 | | 9 | 6 | | 8 | 4 | | 6 | 1 | | 4 | 1 | The answer would be 6 1,2,3,4,5,6,7,8 and we are in the 6 Groupe
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