WEBVTT 0 00:01.280 --> 00:01.760 All right. 1 00:01.760 --> 00:05.570 In this lesson, we're going to learn about a new operator. 2 00:05.570 --> 00:12.740 So similar to the other mathematical operators and the conditional operators, an operator is just a 3 00:12.740 --> 00:17.300 symbol in programming that has a specific function. 4 00:17.660 --> 00:19.940 So what is the modulo operator? 5 00:19.940 --> 00:25.730 Well, it looks a bit like a percentage sign, but it's not just the percentage sign. 6 00:26.420 --> 00:29.000 Instead it goes in between two numbers. 7 00:29.000 --> 00:37.090 So hence a binary operator, and it works out what is the remainder after the division. 8 00:37.090 --> 00:41.080 So 10 / 5 = 2. 9 00:41.080 --> 00:48.700 And this division is clean because five goes into ten two times and there's no remainder. 10 00:48.700 --> 00:58.200 So therefore ten modulo five, if we were to print this out would give us the result of zero (10 % 5 = 0), no remainder 11 00:58.200 --> 00:59.460 in this division. 12 00:59.640 --> 01:01.920 So here's a challenge for you. 13 01:01.950 --> 01:04.920 What is 10 % 3? 14 01:04.920 --> 01:09.030 If 10 / 3 is 3.333333... 15 01:09.120 --> 01:15.120 recurring, because ten does not divide cleanly into three, what do you think would be the result of 16 01:15.120 --> 01:17.400 10 % 3 on a computer? 17 01:18.230 --> 01:19.910 Pause and have a think about it. 18 01:22.160 --> 01:25.070 Okay, so let's go through the solution together. 19 01:25.100 --> 01:33.530 If ten divided by three is equal to three with some decimal places, that means ten does not divide 20 01:33.530 --> 01:34.910 cleanly into three. 21 01:35.120 --> 01:40.640 Ten divided by three is equal to three with one as the remainder. 22 01:40.640 --> 01:47.620 So that means 10 % 3 is going to equal to 1, because all that the modulo does is it performs 23 01:47.620 --> 01:53.500 a division and then gives us how many is remaining after that division. 24 01:53.500 --> 01:58.510 So armed with that knowledge, you are now ready to tackle another coding challenge. 25 01:58.510 --> 02:05.920 And in this coding challenge, I want you to write some code to check whether the number inserted in 26 02:05.920 --> 02:14.520 the input area so typed by a user is odd or even, so you'll need to get hold of what they type in the 27 02:14.520 --> 02:15.450 input area. 28 02:15.450 --> 02:23.250 You'll need to convert it into an integer number, and then you'll need to use an if statement to check 29 02:23.250 --> 02:27.960 and see if you were to modulo that number, 30 02:28.050 --> 02:31.790 is it going to have a remainder? 31 02:31.790 --> 02:39.140 And remember that even numbers, when you use the modulo, 32 02:39.140 --> 02:43.160 so for example let's take an even number, 12. 33 02:43.160 --> 02:51.260 If you use the modulo and you divide that number by two, it's always going to be equal to zero, because 34 02:51.260 --> 02:55.960 any even number divided by two should divide cleanly. 35 02:55.960 --> 03:01.420 So if it divides cleanly with no remainder, then it is an even number. 36 03:01.420 --> 03:02.410 So have a 37 03:02.410 --> 03:07.090 think about this and see if you can complete this challenge. 38 03:07.090 --> 03:14.890 And then later on, in a minute, we will pause the video and then I will come back and explain the solution 39 03:14.890 --> 03:15.520 together. 40 03:15.970 --> 03:17.470 So give it a go now. 41 03:22.140 --> 03:27.000 Okay, so the first thing we need to do is to get hold of an input. 42 03:27.030 --> 03:29.220 Now, it doesn't matter what you ask. 43 03:29.340 --> 03:34.530 You could say, "What is the number you want to check?" 44 03:35.070 --> 03:40.680 And this is going to come out onto here. 45 03:40.680 --> 03:48.480 And then once the user types a number, that number needs to be stored and converted into an integer. 46 03:48.480 --> 03:51.090 So let's do the type conversion first. 47 03:51.090 --> 03:58.680 And then let's create a variable called, number_to_check, and set it equal to this right-hand side. 48 03:58.680 --> 04:01.500 So let's just confirm that that worked. 49 04:01.500 --> 04:06.450 Let's go ahead and hit Run, type in a number, and it gets printed. 50 04:06.450 --> 04:09.260 So that's all working as expected. 51 04:09.980 --> 04:13.730 Now the next thing we need to do is to actually check the number. 52 04:14.270 --> 04:23.990 So if we print the number_to_check % 2, to check if it's even, then we can try this out with 53 04:23.990 --> 04:25.130 some different inputs. 54 04:25.130 --> 04:26.990 So let's try 12. 55 04:26.990 --> 04:29.360 Modulo is zero. 56 04:29.360 --> 04:32.090 Now what if we try an odd number. 57 04:32.090 --> 04:34.360 Let's try a three. 58 04:34.630 --> 04:40.450 Then we get modulo gives us an output of one. 59 04:40.450 --> 04:49.510 So 3 % 2, has a remainder of one, which means it's not even because it does not cleanly divide 60 04:49.510 --> 04:50.440 into two. 61 04:50.470 --> 04:53.710 Let's try another odd number 19. 62 04:53.710 --> 05:02.790 So you can see from this experiment or your knowledge of maths, whatever we take and we modulo 63 05:02.790 --> 05:11.940 it by two if it's equal to zero, if this result is equal to zero, then that means that this number 64 05:11.940 --> 05:13.440 is an even number. 65 05:13.440 --> 05:17.940 So instead of printing this we can use an if statement. 66 05:18.660 --> 05:22.800 If number_to_check % 2 == 0: 67 05:22.800 --> 05:24.060 Now, 68 05:24.060 --> 05:26.550 on an indented 69 05:26.700 --> 05:29.490 line of code, we can say print. 70 05:29.490 --> 05:37.590 Well, this is obviously going to be an even number, and otherwise, so else, then we can print that 71 05:37.590 --> 05:39.810 this is an odd number. 72 05:40.020 --> 05:47.200 So let's just add one space here so that when I run this my cursor just has one space beyond the question 73 05:47.200 --> 05:47.710 mark. 74 05:47.740 --> 05:49.510 Let's check some numbers. 75 05:49.510 --> 05:53.170 45 is odd, which is true. 76 05:53.650 --> 05:56.710 34 should be even. 77 05:56.830 --> 06:04.390 So this is reasonably simple, but it's also quite hard because it uses two things that you've learnt, 78 06:04.390 --> 06:07.360 and it combines them together. 79 06:07.360 --> 06:12.840 So hopefully you managed to get this to work and you manage to write the code yourself. 80 06:12.840 --> 06:16.920 If not, head back to your code and fix it so that it works, 81 06:16.920 --> 06:20.730 after you have seen the solution. There's no shame in seeing the solution, 82 06:20.730 --> 06:22.710 it's all a part of the learning process. 83 06:22.710 --> 06:24.870 Don't worry if you didn't get it first time. 84 06:24.870 --> 06:29.250 There's a lot of things that I didn't get first time as well, but the important thing is you write 85 06:29.250 --> 06:35.220 down notes and you understand what is explained in the lessons so that you're ready to tackle the next 86 06:35.220 --> 06:35.910 challenge.