Giải bài 1, 2, 3 trang 61 vở bài tập toán lớp 4 tập 1 - Tính nhẩm:
\(\eqalign{ & 90000:1000 \times 10 = {\mkern 1mu} {\mkern 1mu} 90 \times 10 \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 900 \cr} \) 1. Tính nhẩm: a) \(\eqalign{& 27 \times 10 = \ldots\cr & 86 \times 10 = \ldots\cr & 358 \times 10 = \ldots\cr} \) \(\eqalign{ & 72 \times 10 = \ldots\cr & 103 \times 10 = \ldots\cr & 1977 \times 100 =\ldots \cr}\) \(\eqalign{ & 14 \times 1000 = \ldots\cr & 452 \times 1000 = \ldots\cr & 300 \times 1000 = \ldots\cr} \) b) \(\eqalign{ \(\eqalign{ \(\eqalign{ c) \(\eqalign{ \(\eqalign{ \(\eqalign{ 2. Tính: a) \(\eqalign{ b) \(\eqalign{ c) \(\eqalign{ d) \(\eqalign{ 3. Viết số thích hợp vào chỗ chấm: a) 160 = 16 × 4500 = × 100 9000 = 9 × c)70000 = × 1000 70000 = ×100 70000 = ×10 b) 8000 = × 1000 800 = ×100 80 = × 10 d)2020000 = × 10000 2020000 = 2020 × 2020000 =× 10 Bài giải: 1. a) \(\eqalign{ \(\eqalign{ \(\eqalign{ b) \(\eqalign{ \(\eqalign{ \(\eqalign{ c) \(\eqalign{ \(\eqalign{ \(\eqalign{ 2. a) \(\eqalign{ b) \(\eqalign{ c) \(\eqalign{ d) \(\eqalign{ 3. a) 160 = 16 × 10 4500 = 45 × 100 9000 = 9 ×1000 c)70000 = × 1000 70000 = ×100 70000 = ×10 b) 8000 = 8× 1000 800 = 8×100 80 = 8× 10 d)2020000 = 202 × 10000 2020000 = 2020 ×1000 2020000 =202000 × 10
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