Question

-21×98

Consider the expression below. Which of these can be used to find the values of the expression?

a) -21×100⁻²
b) -20-1×100⁻²
c) -21×-2+(-21)×100
d) -(-21)×-2+(-21)×100​

Answer 1

None of the suggested methods correctly calculate the expression -21×98, yet option c could be the closest with a slight correction.

Step-by-step explanation:

To find the value of the expression -21×98, we can look at the suggested methods:

• -21×100-2 is not equivalent because it suggests 98 is the same as 98, which is incorrect.
• -20-1×100-2 does not represent the original expression accurately.
• -21×-2+(-21)×100 means adding the product of -21 and -2 to the product of -21 and 100, which does not equal the original expression.
• -(-21)×-2+(-21)×100 simplifies to 42 - 2100, which is not equal to the original expression.

None of these methods correctly represent the expression -21×98. However, option c could be seen as the closest if it were corrected to -21×(-2)+(-21)×100, which would then simplify correctly to represent the original expression.