Aby wykonać podane działania musimy pomnożyć (lub podzielić) współczynniki liczbowe.

a)

$\underset{16}{\underbrace{2\cdot 8}}x=16x$  

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b)

$\underset{-42}{\underbrace{-6\cdot 7}}x=-42x$  

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c)

$\sout{9}{}^{3}z\cdot \frac{2}{\sout{3}{}_1}=6z$  

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d)

$4a\cdot \left(-5\right)=4\cdot \left(-5\right)\cdot a=-20a$  

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e)

$\frac{2}{3}b\cdot 0,75=\frac{2}{{\sout{3}}_1}\cdot \frac{{\sout{3}}^1}{4}\cdot b=\frac{2}{4}b=\frac{1}{2}b$  

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f)

$-1\frac{1}{2}c\cdot \left(-3\frac{1}{3}\right)=1\frac{1}{2}c\cdot 3\frac{1}{3}=1\frac{1}{2}\cdot 3\frac{1}{3}\cdot c=\frac{{\sout{3}}^1}{2}\cdot \frac{10}{{\sout{3}}_1}\cdot c=\frac{10}{2}c=5c$  

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g)

$5\cdot 6x\cdot 2=30x\cdot 2=30\cdot 2\cdot x=60x$  

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h)

$0,2\cdot \left(-5\right)c=-1\cdot c=-c$  

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i)

$32x:4=32x:4=32x\cdot \frac{1}{4}=32\cdot \frac{1}{4}x=8x$  

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j)

$12y:\left(-8\right)=-\frac{12}{8}y=-\frac{3}{2}y=-1\frac{1}{2}y$  

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k)

$\left(-15z\right):\left(-2,2\right)=15z:2,2=150z:22=\frac{150}{22}z=\frac{75}{11}z=6\frac{9}{11}z$  

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l)

$\frac{4}{7}a:\frac{2}{7}=\frac{4}{\sout{7}{}_1}a\cdot \frac{\sout{7}{}^1}{2}=\frac{4}{2}a=2a$