(11)dan (12)
2. pembagian
(7-9)
3.hitungan dengan operasi perkalian dan pembagian
(6-7)
4. hitungan dengan kombinasi empat operasi
(6,13,dan14)
Pembahasan
Yang perlu diketahui
- (+) × (+) atau (+) ÷ (+) = (+)
- (-) × (-) atau (-) ÷ (-) = (+)
- (-) × (+) atau (-) ÷ (+) = (-)
- (+) × (-) atau (+) ÷ (-) = (-)
Untuk penjumlahan dan pengurangan dilihat dari angka (+) dan (-) nya.
Perkalian
- No 11
[tex] \sf ( - \frac{3}{5} ) \times ( + \frac{5}{8} )[/tex]
(-) × (+) hasilnya (-)
[tex] \sf = - \frac{3 \times 5}{5 \times 8} [/tex]
[tex] \sf = - \frac{ 15}{40} [/tex]
[tex] \sf = - \frac{15 \div 5}{40 \div 5} [/tex]
[tex] \sf = - \frac{3}{8} [/tex]
- No 12
[tex] \sf 8 \times ( - \frac{1}{4}) \times ( - 7)[/tex]
(+) × (-) × (-) = hasilnya (+)
[tex] \sf = - \frac{8 \times 1}{4} \times ( - 7)[/tex]
[tex] \sf = - \frac{8}{4} \times ( - 7)[/tex]
[tex] \sf = - 2 \times ( - 7)[/tex]
[tex] \sf = 14[/tex]
Pembagian
- No 7
[tex] \sf ( - \frac{2}{3} ) \div 6[/tex]
(-) ÷ (+) hasilnya (-)
[tex] \sf = - \frac{2}{3} \div \frac{6}{1} [/tex]
[tex] \sf = - \frac{2}{3} \times \frac{1}{6} [/tex]
[tex] \sf = - \frac{2 \times 1}{3 \times 6} [/tex]
[tex] \sf = - \frac{2}{18} [/tex]
[tex] \sf = - \frac{(2 \div 2)}{(18 \div 2)} [/tex]
[tex] \sf = - \frac{1}{9} [/tex]
- No 8
[tex] \sf ( - 12) \div ( - \frac{4}{7} )[/tex]
(-) ÷ (-) hasilnya (+)
[tex] \sf = - 12 \times - \frac{7}{4} [/tex]
[tex] \sf = \frac{( - 12) \times ( - 7)}{4} [/tex]
[tex] \sf = \frac{84}{4} [/tex]
[tex] \sf = 21[/tex]
- No 9
[tex] \sf \frac{5}{8} \div ( - \frac{3}{4} )[/tex]
(+) ÷ (-) hasilnya (-)
[tex] \sf = \frac{5}{8} \times - \frac{4}{3} [/tex]
[tex] \sf = - \frac{5 \times 4}{8 \times 3} [/tex]
[tex] \sf = - \frac{20}{24} [/tex]
[tex] \sf = - \frac{20 \div 4}{24 \div 4} [/tex]
[tex] \sf = - \frac{5}{6} [/tex]
Hitungan dengan Operasi Perkalian dan Pembagian
- No 6
[tex] \sf \frac{2}{3} \div ( - \frac{9}{4} ) \times 4[/tex]
(+) ÷ (-) × (+) hasilnya (-)
[tex] \sf = \frac{2}{3} \times ( - \frac{4}{9} ) \times 4[/tex]
[tex] \sf = - \frac{2 \times 4 \times 4}{3 \times 9} [/tex]
[tex] \sf = - \frac{32}{27} [/tex]
[tex] \sf = - 1 \frac{5}{27} [/tex]
- No 7
[tex] \sf \frac{1}{7} \times ( - \frac{10}{9} ) + ( - \frac{5}{14} )[/tex]
(+) × (-) + (-) hasilnya (-)
[tex] \sf = - \frac{1 \times 10}{7 \times 9} + ( - \frac{5}{14} )[/tex]
[tex] \sf = - \frac{10}{63} + ( - \frac{5}{14} )[/tex]
[tex] \sf = - \frac{20 }{126} + ( - \frac{45}{126} )[/tex]
[tex] \sf = - \frac{20 + 45}{126} [/tex]
[tex] \sf = - \frac{65}{126} [/tex]
Hitungan dengan Kombinasi Empat Operasi
- No 6
[tex] \sf 4 \times ( - 2) + ( - 14) \div 2[/tex]
(+) × (-) + (-) ÷ (+) hasilnya (-)
[tex] \sf = - 8 + - 7[/tex]
[tex] \sf = - 15[/tex]
- No 13
[tex] \sf \frac{3}{4} + ( - \frac{2}{3}) \div 2[/tex]
(+) + (-) ÷ (+) hasilnya tergantung pada penjumlahan akhir
[tex] \sf = \frac{3}{4} + ( - \frac{2}{3} ) \div \frac{2}{1} [/tex]
[tex] \sf = \frac{3}{4} + ( - \frac{2}{3}) \times \frac{1}{2} [/tex]
[tex] \sf = \frac{3}{4} + ( - \frac{2 \times 1}{3 \times 2} )[/tex]
[tex] \sf = \frac{3}{4} + ( - \frac{2}{6} )[/tex]
[tex] \sf = \frac{3}{4} + ( - \frac{2 \div 2}{6 \div 2} )[/tex]
[tex] \sf = \frac{3}{4} + ( - \frac{1}{3} )[/tex]
[tex] \sf = \frac{9}{12} + ( - \frac{4}{12} )[/tex]
[tex] \sf = \frac{9 + ( - 4)}{12} [/tex]
[tex] \sf = \frac{5}{12} [/tex]
- No 14
[tex] \sf \frac{7}{9} - {( - \frac{1}{3})}^{2} [/tex]
[tex] \sf \frac{7}{9} - ( - \frac{1}{3} \times - \frac{1}{3})[/tex]
[tex] \sf = \frac{7}{9} - \frac{1}{9} [/tex]
[tex] \sf = \frac{6}{9} [/tex]
[tex] \sf = \frac{6 \div 3}{9 \div 3} [/tex]
[tex] \sf = \frac{2}{3} [/tex]
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