1. จงเขียนจำนวนต่อไปนี้ในรูปสัญกรณ์วิทยาศาสตร์
1) 0.002
วิธีทำ
0.002
= \(\mathtt{\frac{2}{1,000}}\)
= \(\mathtt{\frac{2}{10^3}}\)
= 2 x \(\mathtt{\frac{1}{10^3}}\)
= 2 x \(\mathtt{10^{-3}}\)
= 2 x \(\mathtt{\frac{1}{10^3}}\)
= 2 x \(\mathtt{10^{-3}}\)
ตอบ 2 x \(\mathtt{10^{-3}}\)
2) 0.00013
วิธีทำ
0.00013
= \(\mathtt{\frac{13}{100,000}}\)
= \(\mathtt{\frac{1.3 \times 10}{10^5}}\)
= 1.3 x \(\mathtt{\frac{10}{10^5}}\)
= 1.3 x \(\mathtt{10^{1 \, – \, 5}}\)
= 1.3 x \(\mathtt{10^{-4}}\)
= 1.3 x \(\mathtt{\frac{10}{10^5}}\)
= 1.3 x \(\mathtt{10^{1 \, – \, 5}}\)
= 1.3 x \(\mathtt{10^{-4}}\)
ตอบ 1.3 x \(\mathtt{10^{-4}}\)
3) 0.000205
วิธีทำ
0.000205
= \(\mathtt{\frac{205}{1,000,000}}\)
= \(\mathtt{\frac{2.05 \times 100}{10^6}}\)
= \(\mathtt{\frac{2.05 \times 10^2}{10^6}}\)
= 2.05 x \(\mathtt{\frac{10^2}{10^6}}\)
= 2.05 x \(\mathtt{10^{2 \, – \, 6}}\)
= 2.05 x \(\mathtt{10^{-4}}\)
ตอบ 2.05 x \(\mathtt{10^{-4}}\)
4) 0.0000076
วิธีทำ
0.0000076
= \(\mathtt{\frac{76}{10,000,000}}\)
= \(\mathtt{\frac{7.6 \times 10}{10^7}}\)
= 7.6 x \(\mathtt{\frac{10}{10^7}}\)
= 7.6 x \(\mathtt{10^{1 \, – \, 7}}\)
= 7.6 x \(\mathtt{10^{-6}}\)
= 7.6 x \(\mathtt{\frac{10}{10^7}}\)
= 7.6 x \(\mathtt{10^{1 \, – \, 7}}\)
= 7.6 x \(\mathtt{10^{-6}}\)
ตอบ 7.6 x \(\mathtt{10^{-6}}\)
5) 0.0000000819
วิธีทำ
0.0000000819
= \(\mathtt{\frac{819}{10,000,000,000}}\)
= \(\mathtt{\frac{8.19 \times 100}{10^{10}}}\)
= \(\mathtt{\frac{8.19 \times 10^2}{10^{10}}}\)
= 8.19 x \(\mathtt{\frac{10^2}{10^{10}}}\)
= 8.19 x \(\mathtt{10^{2 \, – \, 10}}\)
= 8.19 x \(\mathtt{10^{-8}}\)
ตอบ 8.19 x \(\mathtt{10^{-8}}\)
6) 0.000000400465
วิธีทำ
0.000000400465
= \(\mathtt{\frac{400,465}{1,000,000,000,000}}\)
= \(\mathtt{\frac{4.00465 \times 100,000}{10^{12}}}\)
= \(\mathtt{\frac{4.00465 \times 10^5}{10^{12}}}\)
= 4.00465 x \(\mathtt{\frac{10^5}{10^{12}}}\)
= 4.00465 x \(\mathtt{10^{5 \, – \, 12}}\)
= 4.00465 x \(\mathtt{10^{-7}}\)
ตอบ 4.00465 x \(\mathtt{10^{-7}}\)