Which of these statements is true? Circle your answer. 𝑋 times four-fifths equals 𝑋 times 0.4, 𝑋 times seven-fifths equals 𝑋 times 7.5, 𝑋 times eight-fifths equals 𝑋 times 0.16, or 𝑋 times nine-fifths equals 𝑋 times 1.8.
To determine which statement is true, we’ll need to take each of these fractions and convert them into decimals. To convert four-fifths into a decimal, we need to divide four by five. It’s possible to use the bus stop method. But if we have a calculator, we can just divide four by five which will give us a decimal value of 0.8. If we use a calculator to divide seven by five, we get 1.4. Eight divided by five equals 1.6 and nine divided by five equals 1.8. Out of our four options, only one of them has been calculated correctly: 𝑋 times nine-fifths is equal to 𝑋 times 1.8.
What if we wanted to correct the other three statements? We would say that 𝑋 times 1.8 is equal to 𝑋 times four over five, but it’s not equal to 𝑋 times 0.4. 𝑋 times 1.4 equals 𝑋 times seven-fifths. And finally, 𝑋 times 1.6 equals 𝑋 times eight-fifths. And then, we have the bottom one, which was the only one stated correctly originally: 𝑋 times nine-fifths equals 𝑋 times 1.8.