Solutions by everydaycalculation.com
This multiplication involving fractions can also be rephrased as "What is 21/42 of 20/72?"
2142 × 2072 is 536.
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42×40/72 21/84×20/72 63/42×20/72 21/42×60/72
© everydaycalculation.com