Kelly Hee

By BODMAS rule, do the ÷ before the ×. But actually, as long as you do the ÷ and × before the + and -, and you do it from left to right, it will be fine. (assuming that there are no brackets)

So it does not matter x or ÷ comes first. as long as I can get the answer.. ?

one tip is to group things with ÷ and/or × into "islands" separated by + or -. Use more spacing between + and - to see them clearer. e.g. 250÷5x12 - 10 20÷2x2 - 5x2

Once you understand that you can cancel things in the same "island", you not only get things easier (smaller numbers), you are less likely to make mistakes and get the answer faster.

The reason why these "short cuts" work is because of mathematical laws like the Associative Law (a×b)×c = a×(b×c), Commutative Law a×b = b×a, ... etc

If not wrong, most of the pri sch teachers dont teach "BODMAS" in schools nowadays. Kids are told to solve the order of operation as: (1) Do the bracket first (2) ÷ or × (left to right) (3) + or - (left to right)

"BODMAS" is supposed to be interpreted as "B ODM AS"

If multiplication and division comes, do them from left to right. If addition and subtraction comes, do them from left to right. For example, in the above questions, 250 divided by 5 first, since it is followed by multiplication. Then multiply. I advise my students to do this. Scan through the equation from left to right first. If you see brackets, focus on those expressions inside brackets first. Multiplication and division is one group, so the moment you see them, do them first from left to right. Same goes for addition and subtraction.

Based on the verification here, may I confirm the answers are 590 and 10? Thanks.

OK. Tks for the tip

noted. tks for the tips

This is basic level. After practicing and mastering this, learn to cancel and simplify for greater efficiency.

Remember, multiplication and division are in upper class and addition and subtraction are in lower class. Within a class, no particular order on which one comes first. But if an upper class and lower class comes one after another, then upper class do first. If but if upper class comes one after another or a lower class comes one after another, then can just do left to right. For example, if 24+10x2, then do multiplication first since multiplication is upper class and addition is lower class. If 24+10-2, then do from left to right, since addition and subtraction is in lower class. If 24x10 divide by 2, then do from left to right, since both are in upper class. Hope this helps.

I prefer to think of BODMAS as: B O (or I in Australia) DM AS this is what i usually tell my students as well, i usually tell them to go from left to right within those groups as 10 divided by 2 times 4 is 20 but if they try to do the 2 times 4 first they end up with 10 divided by 8 which is only correct if there were brackets around the 2 times 4.

Yes. :)

It's long school holiday.... dun crack your head just enjoy lah :)

M = 3 units Y = 7 units 10 units = 70 cm 1 unit = 7 cm 7 units = 49 cm

3/7Y=M 3/7Y+Y=70 10/7Y=70 Y=70x7/10=49

Txs for the prompt reply... Isn't the total unit is 7 instead of 10...

No. For this case, the qn stated "the length of M is a fraction of Y" means the numerator represents M n denominator represents Y"

U may double check with ur kid. Am sure his/her teacher should have taught this b4. :)

She herself not confident mdm & myself... I ask to explain it to her so tat she knows when & how to use the methods.... txs so much for explaining. Cheers

Txs Roses Myna

No worries. We share n help one another here. :)

Txs so much mdm... tat builds our confidence...

Haha actually i m a guy. :)

Oh no my apologies sir

No worries!:)

Txs Nicholas Low

Welcome

Hi! Let me give you some hints. Hint 1. Find the lowest common multiple for 4 and 3. Why? This is to find the same number of bookmarks and pens. (You should get an answer between 11 to 15) Hint 2. Once you have that lowest common multiple from Hint 1, find the total cost of the same number of bookmarks and pens. (You will realise the total cost is a factor of $124). Hint 3: Divide $124 by the total cost of the same number of bookmarks and pens by $31. (The answer is somewhere between 1 to 5) Hint 4: Use your answer from Hint 3 and multiply it to the lowest common multiple in Hint 1. That will help you solve the question. :)

My son's method: Equal number of pens and bookmarks Pens - 3 6 9 12 Bookmarks - 4 8 12 4 × $4=$16 3 × $5=$15 $15+16=31 $124/31=4 12x4 = 48 pens and 48 bookmarks =96 altogether

Thank you Shaoyang Brandon and Kathleen.