Solving simple equations (positive numbers only)

Lecture




An equation is an equality containing a letter whose value must be found.

In the equations, the unknown is usually denoted by a lowercase Latin letter. The most commonly used letters are “x” [x] and “y” [play].

  • The root of the equation is the value of the letter at which the correct numerical equality is obtained from the equation.
  • Solving an equation means finding all its roots or making sure that there are no roots.

Having solved the equation, we always write a check after the answer.

Information for parents

Dear parents, we would like to draw your attention to the fact that in elementary school and in the 5th grade children DO NOT know the subject “Negative numbers”. Therefore, they must solve equations using only the properties of addition, subtraction, multiplication and division. Methods for solving equations for grade 5 are given below.

Do not try to explain the solution of equations through the transfer of numbers and letters from one part of the equation to another with a change of sign.

Refresh knowledge on concepts related to addition, subtraction, multiplication and division, you can in the section "Laws of arithmetic".

Solving equations for addition and subtraction

What to find Term

x + 9 = 15 		Minuend

x - 14 = 2 		Subtrahend

5 - x = 3
Rule

To find the unknown term, we must take away the known term from the sum.

To find the unknown deductible, add the deductible to the difference.

To find the unknown deductible, it is necessary to subtract the difference from the deductible.

Solution example x + 9 = 15
x = 15 - 9
x = 6
Check

6 + 9 = 15
15 = 15 		x - 14 = 2
x = 14 + 2
x = 16
Check

16 - 2 = 14
14 = 14 		5 - x = 3
x = 5 - 3
x = 2
Check

5 - 2 = 3
3 = 3

The solution of equations for multiplication and division

What to find Factor

y • 4 = 12 		Dividend

y: 7 = 2 		Divider

8: y = 4
Rule

To find an unknown factor, it is necessary to divide the product into a known factor.

To find the unknown dividend, you need to multiply the quotient by the divisor.

To find an unknown divider, it is necessary to divide the dividend into the particular.

Solution example y • 4 = 12
y = 12: 4
y = 3
Check

3 • 4 = 12
12 = 12 		y: 7 = 2
y = 2 • 7
y = 14
Check

14: 7 = 2
2 = 2 		8: y = 4
y = 8: 4
y = 2
Check

8: 2 = 4
4 = 4

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Arithmetic

Terms: Arithmetic