I am doing 4th grade number sense are there any cool math tricks or short cuts that would be good for me to know.
what kind of questions are you doing?
here is a neat one:
multiply any number by 11
e.g. 45821 x 11 = 504031
starting from the right, add up all the digits in the odd positions
1+0+0 = 1
now add up the ones in the even positions
3+4+5 = 12
What is the difference between them ?
I will always be a multiple of 11, that is, 11 22 33 etc
The difference could also be zero, zero is considered a multiple of 11.
Absolutely! There are several math tricks and shortcuts that can help you with number sense. Here are a few fun ones to get you started:
1. Multiplying by 9: To quickly multiply a number by 9, simply write the number down, then subtract 1 from the original number to get the digit in the tens place, and subtract that digit from 9 to get the digit in the ones place. For example, to multiply 5 by 9, write down 5, subtract 1 to get 4, and subtract 4 from 9 to get 5. So, 5 multiplied by 9 is 45.
2. Multiplying by 11: To multiply a number by 11, write down the number, then add the individual digits together, and place the sum in between the original number's digits. For example, to multiply 6 by 11, write down 6, add 6 to 0 (since there's nothing on the left side of 6), and place the sum (6) between the original digits. So, 6 multiplied by 11 is 66.
3. Adding or subtracting multiples of 10: When adding or subtracting multiples of 10, you can simply move the digit(s) to the left or right without changing them. For instance, to subtract 30 from 97, just mentally move the digits in 97 one place to the left, resulting in 67.
4. Multiplying by 5: To multiply a number by 5, you can divide it by 2 and then multiply by 10. For example, to multiply 8 by 5, divide 8 by 2 (which is 4), and then multiply by 10, resulting in 40.
These tricks are simple and handy shortcuts that can help you solve math problems more quickly. Remember, practice makes perfect, so the more you work with these tricks, the easier they will become.