Maths Tricks in Miss Joh's class

In Miss Joh's maths classes we have been exploring maths tricks. These magic maths tricks are fun ways to practice our mathematical skills.   
Your children are looking forward to sharing their magic with you.  These can be a fun way to amaze your relative over the holidays.

 1. Calculating the Square of any Number that Ends with the Digit 5

Calculation of squares is a tough task. But for the set of numbers that end with 5, this can be quite easier than before.

• Let’s take the number 95 and attempt to find its square.
• As per the trick, start by writing the last two digits of the answer, which is 25 (the last two digits of the square of any number that ends with a 5 is 25).
• Now, the first digit in 95 is 9. The number that follows 9 is 10.
• Multiply 9 and 10 to get the answer, which is 90.
• Write 90 in the prefix of the 25 we already wrote as the answer. This makes the complete solution is 9025.

2) This is the magic of the number 1089. By making use of specific calculations, no matter what 3-digit number is chosen, the answer will always turn out to be 1089. Here’s how.

• Let’s choose the number 537.
• Now the digits need to be rearranged in a descending order, 753. This is your first number.
• Rearrange the same digits in the ascending order, 357. This is your second number.
• Subtract the second from the first, which will give us the answer, 753 – 357 = 396.
• Now reverse the order of digits of the answer to getting the number, 693.
• Let’s add both numbers, 396 + 693 = 1089, which we already knew.

Easily Finding the Answer to any Number Multiplied by 11

Most children do end up memorizing the multiplication tables up to 10. But this can be taken one step further by knowing how to quickly multiply with 11 as well.
Let’s try multiplying 45 with 11.

• Separate the digits, 4 and 5 with a space between them, such as 4 [ ] 5.
• Now, carry out the addition of the two digits in the centre, such as 4 [4+5 = 9] 5.
• That’s your answer. 45 x 11 = 495.
• If the sum happens to be a two digit number, such as with 56, which yields 5 [11] 6, simply add the tens place of the sum with the first digit.
• This would then be [5+1 = 6] [1] 6, making the answer as 616.