Можете помочь с 4 номером

Question

Можете помочь с 4 номером

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Answer 1

7860× 1500 =1500× 7860
5879×(8×50) 《 5879 × 800
(2368 × 5)× 4 《 2368×(5×5)
3489 +700586《700586 + 3490
(689+ 3689)×150= 150×689 + 150× 3689
21684+(168954+ 3547)《 (21684 +168955)+3547

Answer 2

Помоему так:7860×1500=7860×1500                                                                                   5879×(8×50)≤5879×800                                                                                         (2368×5)×4≥2368×(5×5)                                                                                        (689+3689)×150≤689×150+3689×150                                                                  21684+(168954+3547)≤3547+(21684+168955)                                        как то так ^_^