The U.S. national debt was $2.9617 \times 10^{13} in 2021 and $3.98 \times 10^{11} in 1971. Find how much the debt increased in the 50-year period. (1 point)

$2.9219 \times 10^{13}

$1.0183 \times 10^{24}

$3.0015 \times 10^{13}

$2.9219 \times 10^{11}

1 answer

To find the increase in the U.S. national debt from 1971 to 2021, we need to subtract the debt in 1971 from the debt in 2021.

The debt in 2021 is: \[ 2.9617 \times 10^{13} \]

The debt in 1971 is: \[ 3.98 \times 10^{11} \]

To perform the subtraction, it's helpful to express both values with the same exponent. We can rewrite \(3.98 \times 10^{11}\) with a base of \(10^{13}\):

\[ 3.98 \times 10^{11} = 0.0398 \times 10^{13} \]

Now we can subtract the two values:

\[ 2.9617 \times 10^{13} - 0.0398 \times 10^{13} = (2.9617 - 0.0398) \times 10^{13} \]

Calculating \(2.9617 - 0.0398\):

\[ 2.9617 - 0.0398 = 2.9219 \]

Thus, the increase in the national debt is:

\[ 2.9219 \times 10^{13} \]

Now, looking at the options provided, the correct answer is:

\[ \boxed{2.9219 \times 10^{13}} \]