Introduction finding missing numbers
Mathematics is all about problem-solving and critical thinking. Finding missing numbers is an essential skill that students should learn to apply mathematical concepts to real-life situations. This skill can be used in various scenarios like balancing a checkbook, solving word problems, and completing calculations. In this article, we will discuss how to find missing numbers using addition and subtraction.
Finding missing numbers using addition
To begin with, we can start with simple addition sentences. Ask students to write down “_ + _ = 12”. Then ask them to think of two numbers that give the sum of 12. Encourage them to come up with different combinations of numbers like 1 + 11, 2 + 10, 3+9, 4 + 8, 5+ 7, 6+6. This exercise will help students understand that there can be multiple solutions to one problem.
Finding missing numbers using subtraction
After discussing addition, move to subtraction. Write down “_ – _ = 14” and ask students to think of two numbers that give 14 when subtracted. Encourage them to come up with different combinations of numbers like 15 – 1, 16 – 2, 17 – 3, 20 – 6, etc. This exercise will help students understand that there can be multiple solutions to one problem.
Finding missing numbers in equations
Next, move on to finding missing numbers in equations. Draw a triangle with three numbers shown in it. Add two numbers and write the sum at the top of the triangle. Then ask students to subtract any bottom number from the sum, and the other number will be the answer. For example, if the top number is 9, and the bottom numbers are 4 and 5, then 9 – 4 = 5, or 9 – 5 = 4. Then, place a missing number in the triangle and ask students to find the value of the missing number.
For example, if the triangle shows 4, 5, and w, and the sum is 9, ask students to find the missing number w. By subtracting 4 or 5 from 9, they will find that the missing number w is 2.
After understanding the concept, write an addition equation on the board like “8 + w = 10”. Ask students to find the value of the missing number. Encourage them to use subtraction to find the missing number. If they add 2 to 8, the sum will be 10. So, the missing number w is 2.
Next, write “k + 4 = 20” on the board and ask students to find the value of the missing number. Encourage them to use subtraction to find the missing number. Subtracting 4 from 20 will give the value of k, which is 16.
Conclusion on finding missing numbers
Finding missing numbers is an essential skill that students should learn to apply mathematical concepts to real-life situations. The skill involves using addition and subtraction to find the value of the missing number in an equation. Encourage students to practice this skill by creating different problems and working in pairs to find the solutions. With regular practice, students will be able to apply this skill in various mathematical scenarios.
