Question

Estimate each of the following using general rule:

$28292-21496$

Make ten more such examples of addition, subtraction and estimation of their outcome.

Answer 1

$28292-21496$

On rounding off the numbers to thousands we get

$28292$ On rounding off the numbers to $28000$

$21496$ On rounding off the numbers to $21000$

Consider

$$\begin{gathered} 28292-21496 \\ 29000-21000 \\ 7000 \end{gathered}$$

Hence, $28292-21496$ is $16000$

Ten more such examples are

$$\begin{gathered} \left(i\right)530+480=500+500=1000 \\ \left(ii\right)2937+3990=3000+4000=7000 \\ \left(iii\right)5321–3321=5000–3000=2000 \\ \left(iv\right)8763–4889=9000–5000=4000 \\ \left(v\right)3005+8675=3000+9000=12000 \\ \left(vi\right)67000–5689=7000–6000=1000 \\ \left(vii\right)8304+5739=8000+6000=14000 \\ \left(viii\right)789–534=800–500=300 \\ \left(ix\right)0498+9304=500+9000=9500 \\ \left(x\right)3098–0938=3000–900=2100 \end{gathered}$$