1. จงหาผลหาร
1) 2.8 \(\div\) 4
ตอบ 0.7
2) 0.45 \(\div\) (-100)
วิธีทำ
0.45 \(\div\) (-100)
= \(\mathsf{\frac{0.45}{(-100)}}\)
= – \(\mathsf{\frac{0.45}{100}}\)
= -0.0045
ตอบ -0.0045
3) (-13.76) \(\div\) (-3.2)
วิธีทำ
(-13.76) \(\div\) (-3.2)
= 13.76 \(\div\) 3.2
= \(\mathsf{\frac{13.76}{3.2} \times \frac{10}{10}}\)
= \(\mathsf{\frac{137.6}{32}}\)
= 4.3
ตอบ 4.3
4) (-250) \(\div\) (-0.8)
วิธีทำ
(-250) \(\div\) (-0.8)
= 250 \(\div\) 0.8
= \(\mathsf{\frac{250}{0.8} \times \frac{10}{10}}\)
= \(\mathsf{\frac{2,500}{8}}\)
= 312.5
ตอบ 312.5
5) (-0.07) \(\div\) 0.07
วิธีทำ
(-0.07) \(\div\) 0.07
= -(0.07 \(\div\) 0.07)
= -1
ตอบ -1
6) (-0.7) \(\div\) (-0.8)
วิธีทำ
(-0.7) \(\div\) (-0.8)
= 0.7 \(\div\) 0.8
= \(\mathsf{\frac{0.7}{0.8} \times \frac{10}{10}}\)
= \(\mathsf{\frac{7}{8}}\)
= 0.875
ตอบ 0.875
7) 5.4 \(\div\) (-0.6)
วิธีทำ
5.4 \(\div\) (-0.6)
= -(5.4 \(\div\) 0.6)
= -(\(\mathsf{\frac{5.4}{0.6} \times \frac{10}{10}}\))
= -(\(\mathsf{\frac{54}{6}}\))
= -9
ตอบ -9
8) (-0.031) \(\div\) (-0.31)
วิธีทำ
(-0.031) \(\div\) (-0.31)
= 0.031 \(\div\) 0.31
= \(\mathsf{\frac{0.031}{0.31} \times \frac{100}{100}}\)
= \(\mathsf{\frac{3.1}{31}}\)
= 0.1
ตอบ 0.1
9) (-0.441) \(\div\) 0.63
วิธีทำ
(-0.441) \(\div\) 0.63
= -(0.441 \(\div\) 0.63)
= -(\(\mathsf{\frac{0.441}{0.63} \times \frac{100}{100}}\))
= -(\(\mathsf{\frac{44.1}{63}}\))
= -0.7
ตอบ -0.7
10) [(-0.015) \(\div\) 0.2] \(\div\) (-0.2)
วิธีทำ
[(-0.015) \(\div\) 0.2] \(\div\) (-0.2)
= (- \(\mathsf{\frac{0.015}{0.2}}\)) \(\div\) (-0.2)
= \(\mathsf{\frac{0.015}{0.2} \div}\) 0.2
= \(\mathsf{\frac{0.015}{0.2} \times \frac{1}{0.2}}\)
= \(\mathsf{\frac{0.015}{0.04}}\)
= \(\mathsf{\frac{0.015}{0.04} \times \frac{100}{100}}\)
= \(\mathsf{\frac{1.5}{4}}\)
= 3.75
ตอบ 3.75