How do you express five eighths in fortieths?

To express five eighths in fortieths, start by converting five eighths into a fraction with a denominator of 40. Since 8 times 5 equals 40, multiply both the numerator and the denominator of five eighths (5/8) by 5:

[ \frac{5 \times 5}{8 \times 5} = \frac{25}{40}. ]

Thus, five eighths is equivalent to twenty-five fortieths.