In this Grade 5 Eureka Math lesson from Chapter 11, students learn how to approximate quotients with two-digit divisors by rounding the divisor to the nearest ten and adjusting the dividend to the nearest compatible multiple. Using mental math strategies, students break division problems like 402 ÷ 19 into simpler steps — for example, estimating as 400 ÷ 20 — to find reasonable estimated quotients. The lesson builds on prior fluency with dividing by multiples of 10 and rounding skills to support efficient mental computation.
Section 1
Finding Compatible Numbers
To set up a division problem for estimation, change the original problem into an approximate problem .
First, round the divisor to the nearest ten to get .
Then, find a compatible number by choosing a multiple of that is close to the original dividend .
Expand to review the lesson summary and core properties.
Section 1
Finding Compatible Numbers
To set up a division problem for estimation, change the original problem into an approximate problem .
First, round the divisor to the nearest ten to get .
Then, find a compatible number by choosing a multiple of that is close to the original dividend .