Quick calculation tips for Android

"Quick calculation tip" is a program that helps you perform calculations: addition, subtraction, multiplication, and division of natural numbers as quickly as possible, with the experience and general knowledge that will help you with mental math. Fastest and most accurate.

With the contents:

• Square 1 of the ends is 5
• Multiply a 2-digit number by 11
• Multiply a number by 5
• Square the number from 50 to 59 .