# How do you add 1.26 x 10^4 +2.5 x 10^3?

You first bring both numbers to the same $10$power
$2.5 \cdot {10}^{3} = 0.25 \cdot {10}^{4}$
because you move the decimal point to the left $10$power goes up .
$1.26 \cdot {10}^{4} + 0.25 \cdot {10}^{4}$
$= \left(1.26 + 0.25\right) \cdot {10}^{4} = 1.51 \cdot {10}^{4}$