To determine which of the given numbers are less than 1,000, we need to calculate each expression:
- \( 8 \times 10^2 = 8 \times 100 = 800 \) (Less than 1,000)
- \( 8 \times 10^2 = 8 \times 100 = 800 \) (Same as above, still less than 1,000)
- \( 9 \times 10^3 = 9 \times 1000 = 9000 \) (Greater than 1,000)
- \( 9 \times 10^3 = 9 \times 1000 = 9000 \) (Same as above, still greater than 1,000)
- \( 5 \times 10^1 = 5 \times 10 = 50 \) (Less than 1,000)
- \( 5 \times 10^{13} = 5 \times 10^{13} \) (Equivalent to 5 followed by 13 zeros, which is much greater than 1,000)
- \( 3 \times 10^4 = 3 \times 10000 = 30000 \) (Greater than 1,000)
Based on the calculations above, the numbers that are less than 1,000 are:
- \( 8 \times 10^2 \)
- \( 8 \times 10^2 \)
- \( 5 \times 10^1 \)
Therefore, the correct responses are:
- \( 8 \times 10^2 \)
- \( 8 \times 10^2 \)
- \( 5 \times 10^1 \)