Let's round each number in each expression to the nearest hundred, then match the expressions on the left with its estimated result on the right.
To round to the nearest hundred, check if the number in the number in tens place is equal or greater than 5, if it is equal or greater than 5 we are to round up by replacing the tens and unit numbers with 0 and adding 1 to the hundreds values. If the tens place value is less than 5 replace the tens and unit with 0.
We have the following:
Expression 1:
2259 + 1189 + 545
Round to the nearest hundred:
2259 ==> 2300
1189 ==> 1200
545 ==> 500
Evaluate:
2300 + 1200 + 500 ==> 4000
Expression 2:
4051 - 49
Round to the nearest hunderd:
4051 ==> 4100
49 ==> 0
Evaluate:
4100 - 0 ==> 4100
Expression 3:
2187 + 2005
Round to the nearest hundred:
2187 ==> 2200
2005 ==> 2000
Evaluate:
2200 + 2000 ==> 4200
Expression 4:
101 + 242 + 363 + 3636
Round to the nearest hundred:
101 ==> 100
242 ==> 200
363 ==> 400
3636 ==> 3600
Evaluate:
100 + 200 + 400 + 3600 ==> 4300
Matching the expressions with the estimated sum or difference, we have:
• 2259 + 1189 + 545 ==> 4000
,
• 4051 - 49 ==> 4100
,
• 2187 + 2005 ==> 4200
,
• 101 + 242 + 363 + 3636 ==> 4300
ANSWER:
• 2259 + 1189 + 545 ==> 4000
,
• 4051 - 49 ==> 4100
,
• 2187 + 2005 ==> 4200
,
• 101 + 242 + 363 + 3636 ==> 4300