Javascript Practice 35: JS Hero - Rounding

 

Question: 

Write a function round100 that rounds a number to the nearest hundred.

Example: round100(1749) should return 1700 and round100(856.12) should return 900.

Answer: 

function round100 (number) { 

return Math.round (number / 100) * 100; 

}; 

> this was a bit tough for me

> i spent almost an hour understanding the logic behind this

> however I did a lot of googling to understand this

> its fairly simple in excel, i checked the function Round in excel

> i also realized that I can always check and experiment on the console to get some hints

> however you are supposed to be good not only in math but mainly in logic to execute this in JS

> this question needed me to round off any number to the nearest 100 

> lets say the number is 149

> lets break the above equation Math.round (number / 100) * 100

number / 100: 149 / 100 = 1.49

Math.round(1.49) =  1 (check this in the debugging console)

Math.round(1.49)*100 =  100

> this maybe easy for a lot of you but I was and am still very weak with Maths & Logic