Solutions by everydaycalculation.com
This multiplication involving fractions can also be rephrased as "What is 21/40 of 42/81?"
2140 × 4281 is 49180.
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/40×42/81 21/40×84/81 21/80×42/81 63/40×42/81
© everydaycalculation.com