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primary 5 | Maths
| Whole Numbers
2 Answers Below
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Hi Tutor, sincerely need your help for this question. Thank you in advanced !
Date Posted: 2 years ago
Views: 444
57 x 28 = box x 7 x 4 - 56 - 3 x 28
Notice that for multiplication, 7 and 4 can be done together (since box, 7 and 4 are multiplied together)
Also notice that 56 = 2 x 28
57 x 28 = box x 28 - 2 x 28 - 3 x 28
Let me replace “28” by “apples”
57 apples = box apples - 2 apples - 3 apples
Does it look better now?
57 = box - 2 - 3
What is the value of box?
62.
Notice that for multiplication, 7 and 4 can be done together (since box, 7 and 4 are multiplied together)
Also notice that 56 = 2 x 28
57 x 28 = box x 28 - 2 x 28 - 3 x 28
Let me replace “28” by “apples”
57 apples = box apples - 2 apples - 3 apples
Does it look better now?
57 = box - 2 - 3
What is the value of box?
62.
Thank you Tutor for the good method!!!
See 2 Answers
58 x 28 = 1596
3 x 28 = 84
84 +1596 = 1680
1680 +56 = 1736
1736 / 4 = 434
434 / 7 = 62
3 x 28 = 84
84 +1596 = 1680
1680 +56 = 1736
1736 / 4 = 434
434 / 7 = 62
Hi Tutor, i dun really understand the solution given. Hope you could explain again, thank you!
Thank you Tutor!
Using BODMAS, the order of mathematical operation is as follows:
Brackets->Orders->Division->Multiplication-> Addition‐>Subtraction
In this question, we only focus on Division-> Multiplication-> Addition‐>Subtraction
Hence, subtraction/addition one side does not affect the multiplication/division on the same side and we can solve the question like so:
57×28=⬜×7×4-56-3x28
1596=⬜×7×4-56-84
1596=⬜×7×4-140
To bring the -140 over to the left side,
Add +140 on both sides
1596+56+84=⬜×7×4-140+140
1736=⬜×7×4
⬜=1736÷7÷4
⬜=62
Hope this helps you to understand better :)
Brackets->Orders->Division->Multiplication-> Addition‐>Subtraction
In this question, we only focus on Division-> Multiplication-> Addition‐>Subtraction
Hence, subtraction/addition one side does not affect the multiplication/division on the same side and we can solve the question like so:
57×28=⬜×7×4-56-3x28
1596=⬜×7×4-56-84
1596=⬜×7×4-140
To bring the -140 over to the left side,
Add +140 on both sides
1596+56+84=⬜×7×4-140+140
1736=⬜×7×4
⬜=1736÷7÷4
⬜=62
Hope this helps you to understand better :)
Definitely! Thank you for your detailed explanation!
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