Introduction To One Step Equation

  • 3 months ago
Transcript
00:00Hi kids! Today we will learn our one-step mathematical equation, so let's get started.
00:10Kids, we write our mathematical problems or questions in the form of equations.
00:18Let's start with addition equation.
00:23One number must be added to 5 to get 20.
00:29We can write this mathematical question in the form of an equation, like this.
00:37We can replace the question mark with any alphabet, like A, B, C, X, or Y,
00:47and our equation becomes 5 plus X equals 20.
00:54So we have to find out the value of X.
00:57Here, 5 plus X is LHS, left-hand side of equation.
01:0520 is RHS, right-hand side of equation.
01:12In any equation, the value of LHS must be equal to RHS.
01:20That is, 5 plus X must be equal to 20.
01:25Now, let's learn how do we solve equations to find the value of X.
01:32Let X be on LHS and shift the other number on RHS.
01:40And while doing this, remember, whenever we shift any number from LHS to RHS or RHS to LHS,
01:52we have to reverse the sign.
01:55That is, plus, we make it minus.
01:59On, if it's minus, we make it plus.
02:05If it's multiplication, we make it division.
02:10If it's division, we make it multiplication.
02:15We will see many examples to clear our concept, and you will find it very easy at the end.
02:23So we have 5 plus X equals 20.
02:29Retaining only X on LHS, it becomes X equals 20 minus 5,
02:38as the sign before 5 is plus on LHS.
02:44No sign means positive number or plus sign.
02:49So, it will be minus on RHS.
02:5520 minus 5 equals 15.
02:59So, X equals 15.
03:02Now you can cross-check your answers too, by putting the value of X in the original equation.
03:11Our original equation is 5 plus X equals 20.
03:18Now putting the value of X, we just found it's 15.
03:235 plus 15 equals 20.
03:27Now check it, 5 plus 15 equals 20.
03:32So, LHS equals RHS.
03:36Hence, we proved the value of X we found is correct.
03:42Let's take another example.
03:45Subtraction equation.
03:48If we subtract 12 from a number, it gives 36.
03:54Then, what is the number?
03:57We can write this mathematical question in the form of an equation.
04:03X minus 12 equals 36.
04:08That is, if we subtract 12 from X, it will give 36.
04:14Now we have to find the value of X to find the number.
04:19Here, X minus 12 is LHS.
04:2436 is RHS.
04:27And, in any equation, LHS must be equal to RHS.
04:34Now, let's find the value of X.
04:38Let X be on LHS and shift the other number on RHS.
04:45While doing this, we know we have to make the signs opposite.
04:50So, it will be X equals 36 plus 12.
04:5736 plus 12 equals 48.
05:01So, X equals 48.
05:04Now you can cross-check your answer, too, by putting the value of X in the original equation.
05:12Our original equation is X minus 12 equals 36.
05:19And when we find out X equals 48, now put this value in equation.
05:2648 minus 12 equals 36.
05:31Now check. 48 minus 12 equals 36.
05:37So, our LHS equals RHS.
05:41Hence, the value of X we found is correct.
05:46Now let's take another equation.
05:49If we multiply 9 by a number, it gives 81.
05:55Then, what is the number?
05:58We can write this mathematical question in the form of an equation.
06:04X multiplied by 9 equals 81.
06:09That is, any number multiplied with 9 gives 81.
06:15And we have to find the number.
06:18Here, X multiplied by 9 is LHS.
06:2481 is RHS.
06:27Now we have to find out the value of X.
06:31What we do here is, let X be on LHS and shift the other number on RHS.
06:40And while doing this, remember, whenever we shift any number from LHS to RHS or RHS to LHS,
06:51we have to reverse the sign before the number.
06:56So we have X multiplied by 9 equals 81, retaining only X on LHS.
07:06We get X equals 81 divided by 9, as the sign before 9 is multiplied in LHS.
07:18So, it will be division on RHS.
07:2381 divided by 9 equals 9.
07:27X equals 9.
07:30Now you can cross-check your answer too, by putting the value of X in the original equation.
07:37Our original equation is, X multiplied by 9 equals 81.
07:45And we found X equals 9.
07:49Now put this value in the equation.
07:52Putting the value, we get 9 multiplied by 9 equals 81.
07:59Check.
08:0081 equals 81, so LHS equals RHS.
08:07Hence, the value of X we found is correct.
08:11Now let's take another example.
08:14If we divide a number by 4, it gives 25.
08:19What is the number?
08:22We can write this mathematical question in the form of an equation.
08:27X divided by 4 equals 25.
08:32Where?
08:34X divided by 4 is LHS.
08:38Now let's find out the value of X.
08:41What we do here is, let X be on LHS, and shift the other number on RHS.
08:49And while doing this, remember, we have to reverse the signs before the numbers in LHS.
08:58So, retaining only X on LHS, we get, X equals 25 multiplied by 4.
09:09As the sign before 4 was division, so it will change to multiplication on RHS.
09:18Solving it, we get, X equals 100.
09:23So we can cross-check your answer too, by putting the value of X in our original equation.
09:31Our original equation is, X divided by 4 equals 25.
09:38And we found X equals 100.
09:42Now put this value in the equation.
09:46Putting the value 100, we get, 100 divided by 4 equals 25.
09:54Now check, 25 equals 25.
09:58So LHS equals RHS.
10:02Hence, the value of X we found is correct.
10:06So kids, today we learned one-step equations, and how to solve them to find out the value of X.
10:14And how to cross-check your answers, by putting the value of X you just find out.
10:21Now you may go ahead and take a quiz to learn more.
10:25Bye-bye.