Вправи 601 - 674 » 620-621

620. Округли до сотень кожне число. 378 ≈ 400, 487 ≈ 500, 189 ≈ 200, 538 ≈ 500, 690 ≈ 700, 370 ≈ 400, 809 ≈ 800 621. 349 – 9 – 40 = 340 – 40 = 300 670 – 70 + 5 = 600 + 5 = 605 581 – 80 – 1 = 501 – 1 = 500 3 + 300 = 303 30 + 900 = 930 99 + 100 = 199 (420 – 400) : 4 = 20 : 4 = 5 7 · (810 – 800) = 7 · 10 = 70 (550 – 500) : 5 = 50 : 5 = 10