I can't remember multiplication tables, is there any math trick for multiplication?


closed as too broad by Shailesh, ervx, Morgan Rodgers, iadvd, pjs36 Feb 9 '17 at 4:49

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    $\begingroup$ Do you know how to multiply numbers which are not decimals? Like $23 \times 518$ for example? $\endgroup$ – shardulc Feb 9 '17 at 2:55
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    $\begingroup$ I have difficulty with multiplying or dividing decimal $\endgroup$ – Sid Patil Feb 9 '17 at 2:57
  • $\begingroup$ Yes, but can you multiply or divide numbers that are not decimals? $\endgroup$ – shardulc Feb 9 '17 at 3:04
  • $\begingroup$ Ya i can multiply those normal 🔢 numbers $\endgroup$ – Sid Patil Feb 9 '17 at 3:05

Basically you count the number of decimals,

Consider $$45.2 \times 2.34$$

You do $$452 \times 234 = 105768$$

Notice how 45.2 has a decimal "one place" to the right, and 2.34 has a decimal "two places" to the right. Adding them up, we get "3 places to the right", for a final answer of $105.768$

  • $\begingroup$ Got the point thank you stack mate $\endgroup$ – Sid Patil Feb 9 '17 at 3:15
  • $\begingroup$ Good thing I still commented even after you accepted an answer! No problem! $\endgroup$ – K Split X Feb 9 '17 at 4:10

Just do simple multiplication of numbers and place the decimal on the correct position
For Example:$$2.3\times5.18$$ Step $1:\text{Simple multiplication}$ $$23\times518=11914$$ Step $2:\text{Place the decimal}$ $$=11.914$$

  • $\begingroup$ Is there any logic behind shifting points $\endgroup$ – Sid Patil Feb 9 '17 at 3:11
  • $\begingroup$ Where should the decimal be placed? What if both numbers are decimals? Please clarify your answer, thanks! $\endgroup$ – shardulc Feb 9 '17 at 3:11
  • $\begingroup$ I mean what if two ✌ decimals and do a division ➗ $\endgroup$ – Sid Patil Feb 9 '17 at 3:12
  • $\begingroup$ @shardulc Add the number of decimal places together. For example, from the answer above, $2.3$ has $1$ decimal place. $5.18$ has $2$ decimal places. So, the result will have $1+2 = 3$ decimal places. Also see the answer above this one. $\endgroup$ – Timothy Cho Feb 11 '17 at 0:14

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