\(a,=461-78+40-461=\left(461-461\right)+\left(-78+40\right)\\ =0+\left(-38\right)=-38\)
\(b,=53-76+76-53=\left(53-53\right)+\left(-76+76\right)=0\)
\(c,=-564-724+564+224=\left(-564+564\right)+\left(-724+224\right)\\ =0-500=-500\)
\(d,=-87-12+487+512=\left(-87+487\right)+\left(-12+512\right)\\ =400+500=900\)
\(e,=\left(942-1942\right)+\left(-2567+2563\right)=-1000+\left(-4\right)=-1004\)
\(f,=\left[17+\left(-20\right)\right]+\left[23+\left(-26\right)\right]+...+\left[53+\left(-56\right)\right]\\ =\left(-3\right)+\left(-3\right)+...+\left(-3\right)\)
có 7 cập số nên
\(=\left(-3\right)\cdot7=-21\)
\(g,=1152-374-1152-65+374=\left(1152-1152\right)+\left(-374+374\right)-65\\ =0+0-65=-65\)
\(h,=-2005-21+75+2005=\left(-2005+2005\right)+\left(75-21\right)\\ =0+54=54\)
