Question

1) -3.7+ 3.17

2) (-21).(-60)- 21.40

3) 20.(-60)-20.(-40)-100.20

4) 21.[(-27)+50+127]

Answer 1

\(a,-3.7+3.17\\ =3.\left(-7\right)+3.17\\ =3.\left(-7+17\right)\\ =3.10\\ =30\\ b,\left(-21\right).\left(-60\right)-21.40\\ =21.60-21.40\\ =21.\left(60-40\right)\\ =21.20\\ =420\\ c,20.\left(-60\right)-20.\left(-40\right)-100.20\\ =20.\left[-60-\left(-40\right)-100\right]\\=20.\left(-120\right)\\ =-2400\\ d,21.\left[\left(-27\right)+50+127\right]\\ =21.\left(100+50\right)\\ =21.150\\ =3150\)

Answer 2

1)  -3.7+3.17= 30

2)  (-21).(-60)-21.40=420

3)  20.(-60)-20(-40)-100.20=(-2400)

4)  3150