. General Information
Subject Area: Mathematics (B.E.S.T.)
Grade: 8
Strand: Number Sense and Operations
Date Adopted or Revised: 08/20
Status: State Board Approved
Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- Scientific Notation
Vertical Alignment
Previous Benchmarks
Next Benchmarks
Purpose and Instructional Strategies
In grade 7, students developed an understanding of Laws of Exponents (Appendix E) with numerical expressions. They focused on generating equivalent numerical expressions with whole-number exponents and rational number bases. In grade 8, students use the knowledge of Laws of Exponents to work with scientific notation. In Geometry, students will solve problems involving density in terms of area and volume which can be represented using scientific notation when the numbers are large. Additionally, students can apply their scientific notation knowledge in science courses.- Instruction connects the work of scientific notation with the Laws of Exponents with integer exponents.
- Instruction includes having students color code or use a highlighter to help keep the numbers together.
- For example, when multiply 3.2 × 1028 and 6.7 × 107, students can highlight the 3.2 and 6.7 in one color and the 1028 and 107 in another color for organizational purposes.
- Students should develop fluency with and without the use of a calculator when performing operations with numbers expressed in scientific notation.
- It is helpful to include contextual problems to compare numbers written in scientific notation, including cross-curricular examples from science.
Common Misconceptions or Errors
- Some students may incorrectly apply addition and subtraction across a problem.
- For example, students may miscalculate (1.3 × 10³) + (3.4 × 105) as 4.7 × 108.
- Some students may incorrectly apply multiplication across a problem.
- For example, students may miscalculate (2 × 104)(3 × 105) as 6 × 1020.
- Some students may incorrectly represent their final answer not in scientific notation.
- For example, students may write (2 × 104)(6 × 105) as 12 × 109 instead of 1.2 × 1010.
Strategies to Support Tiered Instruction
- Instruction includes making connections to the use of place values when adding and subtracting numbers written in standard form to place values with scientific notation.
- Teacher demonstrates how rewriting numbers in scientific notation utilizing the same power of 10 represents numbers with the same place value.
- Instruction includes correct use of operations and laws of exponents when finding the products and quotients of numbers represented in scientific notation, paying close attention to the solution to ensure it is in scientific notation.
- For example, when multiplying (3 × 102) and (4 × 104), students can rearrange the expression as (3 × 4)(102 × 104) to determine 12 × 106 which is equivalent to 1.2 × 107.
- Teacher provides opportunities for students to complete problems using scientific notation and standard form in order to check for the reasonableness of their solutions and build on connections between the two.
Instructional Tasks
Instructional Task 1 (MTR.3.1, MTR.6.1)A collection of meteorites includes three meteorites that weigh 1.1 × 102 grams, 6.8 × 102 grams, and 8.4 × 10−2 grams.
- Part A. Why would a scientist represent the weights using scientific notation? Are all the meteorites approximately the same size?
- Part B. What is the difference between the mass of the heaviest meteorite and the mass of the lightest meteorite? Write your answer in standard notation.
Instructional Items
Instructional Item 1What is the sum of 7 × 10−8 and 6 × 10−8?
Instructional Item 2
Write the expression shown as a number in scientific number.
*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.