8.EE.A.3 math practice. Learn by doing.

8.EE.A.3 practice covers use numbers expressed in the form of a single digit times an integer power of 10 to estimate very large or very small quantities. Work through 8 free questions with answers and explanations, then continue in the related math games.

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8 free questions · 0/0 correct

Practice playmedium

Let f(t)=8e3t+50f(t) = 8e^{3t} + 50. Which of the following approximations, written as a×10na \times 10^n with one significant digit, is closest to the value of f(2)f(2)?

Substitute t=2t = 2: f(2)=8e6+50f(2) = 8e^{6} + 50. Since e6403.4e^{6} \approx 403.4, f(2)8(403.4)+50=3,2773×103f(2) \approx 8(403.4) + 50 = 3{,}277 \approx 3 \times 10^{3}.

Practice playeasy

9×1059 \times 10^5 is how many times as large as 3×1023 \times 10^2?

9×1053×102=3×103=3,000\dfrac{9 \times 10^5}{3 \times 10^2} = 3 \times 10^3 = 3{,}000.

Practice playmedium

Let f(t)=4e3t+200f(t) = 4e^{3t} + 200. Which of the following approximations, written as a×10na \times 10^n with one significant digit, is closest to the value of f(3)f(3)?

Substitute t=3t = 3: f(3)=4e9+200f(3) = 4e^{9} + 200. Since e98,103e^{9} \approx 8{,}103, f(3)4(8,103)+200=32,6123×104f(3) \approx 4(8{,}103) + 200 = 32{,}612 \approx 3 \times 10^{4}.

Practice playeasy

0.0075=c×1030.0075 = c \times 10^{-3}. What is cc?

Moving the decimal in 0.00750.0075 three places right gives 7.57.5, so c=7.5c = 7.5.

Practice playmedium

Let f(t)=4e2t+50f(t) = 4e^{2t} + 50. Which of the following approximations, written as a×10na \times 10^n with one significant digit, is closest to the value of f(4)f(4)?

Substitute t=4t = 4: f(4)=4e8+50f(4) = 4e^{8} + 50. Since e82,981e^{8} \approx 2{,}981, f(4)4(2,981)+50=11,9741×104f(4) \approx 4(2{,}981) + 50 = 11{,}974 \approx 1 \times 10^{4}.

Practice playeasy

Write 45004500 as a×10na \times 10^n where 1a<101 \le a < 10. What is nn?

4500=4.5×1034500 = 4.5 \times 10^3, so n=3n = 3.

Practice playhard

Let f(t)=3e2t+10f(t) = 3e^{2t} + 10. Which of the following approximations, written as a×10na \times 10^n with one significant digit, is closest to the value of f(5)f(5)?

Substitute t=5t = 5: f(5)=3e10+10f(5) = 3e^{10} + 10. Since e1022,026e^{10} \approx 22{,}026, f(5)3(22,026)+10=66,0887×104f(5) \approx 3(22{,}026) + 10 = 66{,}088 \approx 7 \times 10^{4}.

Practice playeasy

(2×103)(3×104)=6×10n(2 \times 10^3)(3 \times 10^4) = 6 \times 10^n. What is nn?

Multiply coefficients (23=62 \cdot 3 = 6) and add exponents: 3+4=73 + 4 = 7, so n=7n = 7.

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