Tag: mental arithmetic

Quizzes (5) Questions (31)

Questions Related to mental arithmetic

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Rohit's teacher asked him to tell the correct answer after performing the steps given.
$\bullet$ Round off $43, 98$ and $250$ to nearest tens.
$\bullet$ After rounding off, add them.
$\bullet$ Round off the sum to the nearest hundreds.
Then, the correct answer is __________.

  1. $300$
  2. $400$
  3. $350$
  4. $480$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Rounding off to nearest tens:

If unit digit is $0,1,2,3,4$ then round down to nearest tens.
If unit digit is $5,6,7,8,9$ then, round up to nearest tens.
$43$ $\rightarrow$ $40$
$98$ $\rightarrow$ $100$
$250$ $\rightarrow$ $250$
$40+100+250$ $\rightarrow$ $390$
$390$  $\rightarrow$  $400$
Hence, Option B is correct.