2. จงหาค่าของจำนวนต่อไปนี้
1) \(\mathtt{(5 + 2)^2}\)
วิธีทำ
\(\mathtt{(5 + 2)^2}\)
= \(\mathtt{7^2}\)
= 7 x 7
= 49
= 49
ตอบ 49
2) \(\mathtt{(-3)(1 + 2)^2}\)
วิธีทำ
\(\mathtt{(-3)(1 + 2)^2}\)
= \(\mathtt{(-3)3^2}\)
= (-3)(3 x 3)
= (-3)(9)
= -27
= (-3)(9)
= -27
ตอบ -27
3) \(\mathtt{(2\frac{1}{3})^3}\)
วิธีทำ
\(\mathtt{(2\frac{1}{3})^3}\)
= \(\mathtt{(\frac{7}{3})^3}\)
= \(\mathtt{\frac{7}{3} \times \frac{7}{3} \times \frac{7}{3}}\)
= \(\mathtt{\frac{343}{27}}\)
= \(\mathtt{\frac{343}{27}}\)
ตอบ \(\mathtt{\frac{343}{27}}\)
4) \(\mathtt{\frac{3^2 \; + \; (2 \; – \; 5)^2}{2^4}}\)
วิธีทำ
\(\mathtt{\frac{3^2 \; + \; (2 \; – \; 5)^2}{2^4}}\)
= \(\mathtt{\frac{(3 \times 3) \; + \; (-3)^2}{2 \times 2 \times 2 \times 2}}\)
= \(\mathtt{\frac{9 \; + \; [(-3) \times (-3)]}{16}}\)
= \(\mathtt{\frac{9 \; + \; 9}{16}}\)
= \(\mathtt{\frac{18}{16}}\)
ตอบ \(\mathtt{\frac{18}{16}}\)
5) \(\mathtt{(2 \; – \; \frac{1}{4})^3}\)
วิธีทำ
\(\mathtt{(2 \; – \; \frac{1}{4})^3}\)
= \(\mathtt{(\frac{8 \; – \; 1}{4})^3}\)
= \(\mathtt{(\frac{7}{4})^3}\)
= \(\mathtt{\frac{7}{4} \times \frac{7}{4} \times \frac{7}{4}}\)
= \(\mathtt{\frac{343}{64}}\)
ตอบ \(\mathtt{\frac{343}{64}}\)
6) \(\mathtt{(6 \times 2)^2}\)
วิธีทำ
\(\mathtt{(6 \times 2)^2}\)
= \(\mathtt{(12)^2}\)
= 12 x 12
= 144
= 144
ตอบ 144
7) \(\mathtt{(2^3)^2}\)
วิธีทำ
\(\mathtt{(2^3)^2}\)
= \(\mathtt{(2 \times 2 \times 2)^2}\)
= \(\mathtt{8^2}\)
= 8 x 8
= 64
= 8 x 8
= 64
ตอบ 64
8) \(\mathtt{[(0.2)^2]^2}\)
วิธีทำ
\(\mathtt{[(0.2)^2]^2}\)
= \(\mathtt{(0.2 \times 0.2)^2}\)
= \(\mathtt{(0.04)^2}\)
= 0.04 x 0.04
= 0.0016
= 0.04 x 0.04
= 0.0016
ตอบ 0.0016