# Adding and subtracting numbers in different bases dating

### Addition and Subtraction with Scientific Notation

This diagram shows the relationship between the various types used to store Times, . To add and subtract periods of time to date and date/time objects, use the Dates. To retrieve the value as a number, use the function smena.info(): .. julia> moment=smena.info() T julia> smena.infot Base. Count to using base-ten numerals, number names, and expanded form. , Adding 9, Number, Addition, Use the jump strategy to add 9 to numbers. , The Calendar, Measurement, Time, Use a calendar to identify the date. . Explore 3 different strategies to subtract two 3-digit numbers: use base 10 equipment. Jul 22, Adding and subtracting with scientific notation may require more care must have exactly the same base numbers to exactly the same powers.

DateTime ,11,11,11,11,11 a Dates.

**Subtracting in Bases**

Sometimes you want UTC the reference time for the world, without local adjustments for daylight savings: For both date and datetime objects, you can obtain the year, month, day, and so on: The last function, dayofweekofmonth birthday day of week of monthtells us that the 15th of March,was the third Saturday of the month.

You can also find days relative to a date, such as the first day of the week containing that day, using the adjusting functions, described below. Subtracting two dates or datetimes to find the difference is the most obvious one: Milliseconds or some other unit: Year 20 defines a period of 20 years, and Dates. Month 6 defines a period of 6 months. So, to add 20 years and 6 months to the birthday date: Month 6 Here's 6 months ago from now: Year 2 - Dates.

Here's the date and time for two weeks and 12 hours from now: To retrieve the value as a number, use the function Dates. To find out which of these fall on weekdays, you can provide an anonymous function to filter that tests the day name against the given day names: Date "" 1 Jan 31 Jan 2 Mar 1 Apr 1 May 31 May 30 Jun 30 Jul 29 Aug 28 Sep 28 Oct 27 Nov 27 Dec Date formatting[ edit ] To specify date formats, you use date formatting codes in a formatting string.

For example, you create a DateTime object from a string by identifying the different elements in the incoming string: DateTime "Fri, 15 Jun In the second example, the formatting characters matched up as follows: Fri, 15 Jun S You can supply a format string to Dates.

## Laws of Exponents

In the formatting string, you repeat the characters to control how years and days, for example, are output: SS" "Tue, 28 Jul DateTime "Tue, 8 Jul 2: MM, e" "28, July, For example, there's Dates. You can do this with the functions like Dates.

So, if we're currently in the middle of the week: With tonext and toprevyou can provide a possibly anonymous function that returns true when a date has been correctly adjusted.

- Introducing Julia/Working with dates and times

For example, the function: I'd be glad to correspond with you further if you have ideas. Number bases other than 10 Dear Dr.

Rick, Thank you for the neat answer. Can the idea be that if the base can be divided evenly by two, then you can tell by looking to see if the last digits are even numbers that the number is an even number? And too, if the base is evenly divisible by 2, and the last digit is an odd number, then the number is odd? If the base number is not evenly divisible by 2, then you can't tell by looking at the last digit whether the number is even or odd.

Thank you again for your help. Number bases other than 10 Hi, Agnes - Yes, you've got the idea. What do you think about divisibility by 3? And why do you think this works?

Rick, The last part of my project is to learn subtraction in other bases. What I am supposed to borrow?

### Number Base Converter

Can you help some more? Number bases other than 10 Hi again, Agnes. Subtraction in other bases isn't very hard; I'll just give you some examples.

The basic rule is that you always borrow the base. For instance, in base 4: Take 1 from the 4's column and change it to four 1's; add the four 1's to the two 1's that you have: We can't subtract 3 from 0, so we need to borrow again.

Take 1 from the 16's column and change it to four 4's; add the four 4's to the zero 4's that you have: You can check your understanding of adding in base 4: