8th Grade · Expressions & Equations
Matching Exponents
8.EE.A.4
Definition
Adjusting numbers in scientific notation so their powers of ten are equal, which is required before adding or subtracting them.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- 4.2 × 105 + 3.0 × 104: rewrite 3.0 × 104 as 0.3 × 105, then add: 4.5 × 105.
- Multiplying and dividing do NOT need matching exponents — only adding and subtracting do.
Key rule
Make the exponents match first, then add or subtract the coefficients.
Memory hook
Match the powers of ten before adding.