Respuesta :

You can try to use the internet for the answer to some of those questions.
1) 25cm2 = 150cm2 (not sure, sorry)
2) 3 • x = 1.8
x = 0.6
(I replaced the gap with the letter x)
3) 1 + 2 + 3 + 4 = 3 + 7 = 10
4) -5 + - 7 + 10 + 10 = -12 + 20 = 8
5) -3 (4 + a) = -12 - 3a