a) 48 x 9 - 48 x 8

= 48 x (9 - 8)

= 48 x 1

= 48

b) 156 x 7 - 156 x 2

= 156 x (7 - 2)

= 156 x 5

= 780

a) 92 + 74 + 26 = 92 + (74 + 26)

= 92 + 100 = 192

b) 12 + 14 + 16 + 18 = (12 + 18) + (14 + 16)

= 30 + 30 = 60

c) 592 + 99 + 208 = (592 + 208) + 99

= 800 + 99 = 899

d) 60 + 187 + 40 + 13 = (60 + 40) + (187 + 13)

= 100 + 200 = 300

\(a)\dfrac{599}{1000}+\dfrac{377}{1000}+\dfrac{1}{1000}\\ =\left(\dfrac{599}{1000}+\dfrac{1}{1000}\right)+\dfrac{377}{1000}\\ =\dfrac{600}{1000}+\dfrac{377}{1000}\\ =\dfrac{977}{1000}\\ b)\dfrac{15}{4}+\dfrac{15}{16}+\dfrac{5}{16}\\ =\dfrac{15}{4}+\left(\dfrac{15}{16}+\dfrac{5}{16}\right)\\ =\dfrac{15}{4}+\dfrac{20}{16}\\ =\dfrac{60}{16}+\dfrac{20}{16}\\ =\dfrac{80}{16}=5\)

a) 3 506 x 25 x 4 

= 3 506 x (25 x 4)

= 3 506 x 100

b) 467 x 46 + 467 x 54

= 467 x (46 + 54)

=467 x 100

 = 46700

a) 3 506 x 25 x 4

=   3506.100

=350600

b) 467 x 46 + 467 x 54

= 467.(46+54)

=467.100

=46700

a) 3 506 x 25 x 4

= 3506 x (25 x 4)

= 3506 x 100

= 350 600

b) 467 x 46 + 467 x 54

= 467 x (46 + 54)

= 467 x 100

= 46 700

a) 67 x 3 + 67 x 7

= 67 x (3 + 7)

= 67 x 10

= 670

b) 45 x 6 + 45 x 4

= 45 x (6 + 4)

= 45 x 10

= 450

c) 27 x 6 + 73 x 6

= 6 x (27 + 73)

= 6 x 100

= 600

a) 73 833 + 3 992 – 3 833 = (73 833 – 3 833) + 3 992

= 70 000 + 3 992 = 73 992

b) 85 600 + 2 500 – 5 600 = (85 600 – 5 600) + 2 500

= 80 000 + 2 500 = 82 500

c) 30 254 + 10 698 + 1 746 = (30 254 + 1 746) + 10 698

= 32 000 + 10 698 = 42 698

\(a,\dfrac{2}{13}\times\dfrac{22}{5}\times\dfrac{13}{2}\\ =\left(\dfrac{2}{13}\times\dfrac{13}{2}\right)\times\dfrac{22}{5}\\ =1\times\dfrac{22}{5}=\dfrac{22}{5}\\ b,\dfrac{3}{5}\times\dfrac{6}{7}+\dfrac{6}{7}\times\dfrac{3}{5}\\ =\dfrac{3}{5}\times\left(\dfrac{6}{7}+\dfrac{6}{7}\right)\\ =\dfrac{3}{5}\times\dfrac{12}{7}=\dfrac{36}{35}\)

\(a,=\left(\dfrac{2}{13}\times\dfrac{13}{2}\right)\times\dfrac{22}{5}=\dfrac{22}{5}\\ b,=\dfrac{3}{5}\times\left(\dfrac{6}{7}+\dfrac{6}{7}\right)\\ =\dfrac{3}{5}\times\dfrac{12}{7}\\ =\dfrac{36}{35}\)

a)

\(\dfrac{3}{5}\times\dfrac{7}{11}\times\dfrac{5}{3}\times11\\ =\left(\dfrac{3}{5}\times\dfrac{5}{3}\right)\times\left(\dfrac{7}{11}\times11\right)\\ =\dfrac{3\times5}{5\times3}\times\dfrac{7\times11}{11}\\ =1\times7\\ =7\)

b)

\(\dfrac{3}{8}\times\dfrac{2}{7}+\dfrac{5}{7}\times\dfrac{3}{8}\\ =\dfrac{3}{8}\times\left(\dfrac{2}{7}+\dfrac{5}{7}\right)\\ =\dfrac{3}{8}\times\dfrac{7}{7}\\ =\dfrac{3}{8}\times1=\dfrac{3}{8}\)

a) \(\dfrac{3}{5}\times\dfrac{17}{21}+\dfrac{2}{5}\times\dfrac{17}{21}\)

\(=\dfrac{17}{21}\times\left(\dfrac{3}{5}+\dfrac{2}{5}\right)\)

\(=\dfrac{17}{21}\times1\)

\(=\dfrac{17}{21}\)

b) \(\dfrac{11}{19}\times\dfrac{2}{7}+\dfrac{5}{7}\times\dfrac{11}{19}\)

\(=\dfrac{11}{19}\times\left(\dfrac{2}{7}+\dfrac{5}{7}\right)\)

\(=\dfrac{11}{19}\times1\)

\(=\dfrac{11}{19}\)

a: =17/21(3/5+2/5)

=17/21*5/5

=17/21

b: =11/19(2/7+5/7)

=11/19*1

=11/19