Question

a student says: we cannot subtract 1.97 from 20 because 20 does not have any hundredths to subtract from. is the student correct? yes no

Explanation:

Step1: Rewrite 20 as a decimal

We can rewrite 20 as \(20.00\) to have the same number of decimal places as 1.97. This is because we can add zeros after the decimal point without changing the value of the number. So, \(20 = 20.00\).

Step2: Subtract 1.97 from 20.00

Now, we subtract \(1.97\) from \(20.00\).
\[

$$\begin{align*} 20.00 - 1.97&=(19 + 1.00)- 1.97\\ &=19+(1.00 - 1.97)\\ &=19+(0.99 + 0.01- 1.97)\\ &=19+(0.99 - 1.97+ 0.01)\\ &=19+(- 0.98 + 0.01)\\ &=19 - 0.97\\ &=18.03 \end{align*}$$

\]
Or directly subtracting:
\[

$$\begin{array}{@{}c@{}c@{}c@{}c@{}} & 20.00 \\ - & 1.97 \\ \cline{1-2} & 18.03 \\ \end{array}$$

\]
Since we were able to subtract 1.97 from 20 (by rewriting 20 as 20.00), the student is incorrect.

Answer:

No