## Indian bride walks out of wedding when groom fails math test

Here’s one more reason to learn math!

NEW DELHI (AP) — An Indian bride walked out of her wedding ceremony after the groom failed to solve a simple math problem, police said Friday.

The bride tested the groom on his math skills and when he got the sum wrong, she walked out.

The question she asked: How much is 15 plus six?

His reply: 17.

The news may seem like a joke, but on a more serious note, the usage of calculators in Primary 5 & Primary 6 has led to a drop in the mental arithmetic standards of children in Singapore! As a tutor, I have clearly observed the difference before and after the calculator usage was introduced. Many a times, students need a calculator to calculate what is 18+15, for example. Also, 8 times 8 (mental calculation) would pose a challenge nowadays to some students ages 9-12, whereas in the past students would know it is 64 in less than a second.

What is happening is that students are getting a bit too reliant on the calculator, and hence their human calculator (a.k.a brain) has lack of training in this aspect. How to remedy it is to practice and train in more multiplication questions.  # Multiply by 9999 trick

Here is a nice trick to multiply a 4 digit number by 9999.

For instance, lets try multiplying 1729 by 9999.

First, we reduce 1729 by 1.

1729-1=1728

Then, we subtract each of the above digits from 9 to get 8271.

(9-1=8, 9-7=2, 9-2=7, 9-8=1)

In conclusion, 9999 x 1729=1728,8271.

Impressive isn’t it?

This trick works for many 9s too, for example multiplying by 99999999.

To multiply 9999 with a number with less digits, for instance, 12, simply pad zeroes in front of the number, to become 0012.

Then, using the above method, 9999 x 0012 = 0011,9988=119988.  Secrets of Mental Math: The Mathemagician’s Guide to Lightning Calculation and Amazing Math Tricks 