Question

a) 37.24 + 37.76 + 63.79 + 21.63

b) 101 + (-60) + 29 + (-40)

c) 40 + (139 – 172 + 99) – (139 + 199 – 127) 

d) (158.129 – 158.39):180

Answer 1

a: \(37\cdot24+37\cdot76+63\cdot79+21\cdot63\)

\(=37\left(24+76\right)+63\left(79+21\right)\)

\(=37\cdot100+63\cdot100\)

\(=100\left(37+63\right)=100\cdot100=10000\)

b: 101+(-60)+29+(-40)

=101+29-(60+40)

=130-100=30

c: \(40+\left(139-172+99\right)-\left(139+199-127\right)\)

\(=40+139-172+99-139-199+127\)

=40+127-100-172

=167-100-172

=67-172=-105

d: \(\dfrac{158\cdot129-158\cdot39}{180}\)

\(=\dfrac{158\left(129-39\right)}{180}\)

\(=158\cdot\dfrac{90}{180}=158\cdot\dfrac{1}{2}=79\)