ГДЗ до підручника «Математика» О.С. Істера. 5 клас

§ 6

231. 1) 572 • 10 = 5720;

2) 100 • 7982 = 798 200;

3) 1000 • 52 = 52 000;

4) 8 • 7 • 5 = 7 • (8 • 5) = 7 • 40 = 280;

5) 7 • 20 • 5 = 7 • (20 • 5) = 7 • 100 = 700;

6) 4 • 8 • 25 = 8 • (4 • 25) = 8 • 100 = 800;

7) 43 • 10 • 2 = (43 • 2) • 10 = 86 • 10 = 860;

8) 5 • 9 • 2 • 7 = (9 • 7) • (5 • 2) = 63 • 10 = 630;

9) 10 • 2 • 7 • 50 = (2 • 50) • 7 • 10 = 100 • 7 • 10 = 7000.

232. 1) 4 • 89 • 25 = (4 • 25) • 89 = 8900;

2) 2 • 472 • 5 = (2 • 5) • 472 = 4720;

3) 5 • 72 • 4 = (5 • 4) • 72 = 1440;

4) 50 • 15 • 2 = (50 • 2) • 15 = 1500;

5) 125 • 14 • 8 = (125 • 8) • 14 = 14000;

6) 8 • 37 • 25 = (8 • 25) • 37 = 200 • 37 = 7400.

233. 1) 25 • 17 • 4 = (25 м 4) • 17 = 1700;

2) 5 • 137 • 20 = 5 • 20 • 137 = 13 700;

3) 6 • 5 • 39 = (6 • 5) • 39 = 30 • 39 = 1170;

4) 500 • 19 • 2 = (500 • 2) • 19 = 19 000;

5) 8 • 115 • 125 = (8 • 125) • 115 = 115 000;

6) 80 • 113 • 5 = (80 • 5) • 113 = 45 200.

234. 1) 6 • 7 • b = 42b;

2) 8 • 9а = 72а;

3) 3 • a • 4 • b = 12ab;

4) 5x • 7y = 35xy;

5) 3 • m • 2a • 7 • t= 42amt;

6) 2a • 3z • 4n = 24azn.

235. 1) 8 • 7 • x = 56x;

2) 17x • 2 = 34x;

3) 5 • x • 9 • m = 45mx;

4) 9a • 11b = 99ab;

5) 5 • x • 9 • 8 • a • m = 360amx;

6) 10b • 20с • 17р = 3400bcp.

236. 1) 387 • 73 + 387 • 27 = 387 • (73 + 27) = 38 700;

2) 842 • 39 + 158 • 39 = 39 • (842 + 158) = 39 000;

3) 18 • 918 - 18 • 818 = 18 • (918 - 818)= 1800;

4) 7292 • 27 - 7292 • 26 = 7292 • (27 - 26) = 7292.

237. 1) 452 • 499 + 452 • 501 = 452 • (499 + 501) = 452 000;

2) 83 • 47 + 917 • 47 = 47 • (83 + 917) = 47 000;

3) 192 • 2005 - 192 • 1005 = 192 • (2005 - 1005) = 192 000;

4) 4592 • 217 - 4592 • 216 = 4592 • (217 - 216) = 4592.

238. 1) 4m + 5m = m • (4 + 5) = 9m;

2) 9х - 5х = x • (9 - 5) = 4х;

3) 10с - 2с = с • (10 - 2) = 8с;

4) 7а + 8а - 5а = а • (7 + 8 - 5) = 10а.

239. 1) 9а + 2а = а • (9 + 2) = 11а;

2) 15b - 3b = b • (15 - 3) = 12b;

3) 4x + 2x - 3x = x • (4 + 2 - 3) = 3х;

4) 10t - 2t - 5t = t • (10 - 2 - 5) = 3t.

240. 1) 5 • (x + 2) = 5 • x + 5 • 2 = 5x + 10;

2) (7 - a) • 9 = 7 • 9 - a • 9 = 63 - 9a;

3) 2 • (3b + 8c) = 2 • 3b + 2 • 8c = 6b + 16c;

4) (5a - 6b) • 2 = 5a • 2 - 6k • 2 = 10a - 12b.