B1:
a) = (8/15 + 7/15) + (7/4 + 5/4)
= 15/15 + 12/4
= 1 + 3
= 4
b) = (16,88 + 3/12) + 9,76
= 20 + 9,76
= 29,76
c) = (17,16 + 82,84) + 72,84
= 100 + 72,84
= 172,84
B2:
2/3 + 4/5 = 10/15 + 12/15 = 22/15
a) \(\frac{8}{15}+\frac{7}{4}+\frac{7}{15}+\frac{5}{4}\)
\(=\left(\frac{8}{15}+\frac{7}{15}\right)+\left(\frac{7}{4}+\frac{5}{4}\right)\)
\(=\frac{15}{15}+\frac{12}{4}\)
\(=1+3=4\)
b) \(16,88+9,76+3,12\)
\(=\left(16,88+3,12\right)+9,76\)
\(=20+9,76=29,76\)
c) \(72,84+17,16+82,84\)
\(=\left(82,84+17,16\right)+72,84\)
\(=100+72,84=172,84\)
\(\frac{2}{3}+\frac{4}{5}=\frac{10}{15}+\frac{12}{15}=\frac{22}{15}\)
8/15+7/4+7/15+5/4
=( 8/15 +7/15)+ (7/4+5/4)
= 1 + 3
= 4
16,88 + 9,76 +3,12
=(16,88+3,12)+9,76
= 20 +9,76
= 29,76
72,84+17,16+82,84
=(72,84+17,16)+82,84
= 90 +82,84
=172,84
