In this Grade 8 lesson from Yoshiwara Core Math, Chapter 7, students learn how to add signed numbers, including adding two numbers with the same sign and adding two numbers with opposite signs. Using number lines and real-world examples like debt and assets, students develop the rules for addition of positive and negative integers and explore the concept of net change. The lesson builds foundational skills for working with signed numbers in algebra and beyond.
Section 1
📘 Adding Signed Numbers
This lesson introduces the rules for adding signed numbers. You'll learn how to combine numbers with the same sign and with opposite signs to find a final value, or 'net change,' a key skill for real-world applications.
Next, you’ll master these rules through interactive examples using number lines and counters. Then, test your skills with practice cards and challenge problems.
Section 2
Adding Two Numbers with the Same Sign
Section 3
Adding Two Numbers with Opposite Signs
The sum of a positive number and a negative number can be either positive or negative. It depends on which is farther from zero.
To find the sum, subtract the unsigned parts of the numbers, and use the sign of the number that is farther from zero.
Section 4
Rules for Addition of Signed Numbers
a. Add the unsigned parts of the numbers.
b. Use the same sign for the sum.
a. Subtract the unsigned parts of the numbers.
b. If the positive number is farther from zero, the sum is positive. If the negative number is farther from zero, the sum is negative.
Section 5
Net Change
We denote gains by positive numbers and losses by negative numbers. We can find the net change in a quantity by adding those gains and losses.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter
Expand to review the lesson summary and core properties.
Section 1
📘 Adding Signed Numbers
This lesson introduces the rules for adding signed numbers. You'll learn how to combine numbers with the same sign and with opposite signs to find a final value, or 'net change,' a key skill for real-world applications.
Next, you’ll master these rules through interactive examples using number lines and counters. Then, test your skills with practice cards and challenge problems.
Section 2
Adding Two Numbers with the Same Sign
Section 3
Adding Two Numbers with Opposite Signs
The sum of a positive number and a negative number can be either positive or negative. It depends on which is farther from zero.
To find the sum, subtract the unsigned parts of the numbers, and use the sign of the number that is farther from zero.
Section 4
Rules for Addition of Signed Numbers
a. Add the unsigned parts of the numbers.
b. Use the same sign for the sum.
a. Subtract the unsigned parts of the numbers.
b. If the positive number is farther from zero, the sum is positive. If the negative number is farther from zero, the sum is negative.
Section 5
Net Change
We denote gains by positive numbers and losses by negative numbers. We can find the net change in a quantity by adding those gains and losses.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter