Learning Objectives
- 01
Divide by a 2-digit number with a sensible quotient guess.
Two-Digit Division
Estimate, then refine.
Topics
2-digit divisors
Worked Examples
353 ÷ 14=25 r 3
500 ÷ 73=6 r 62
2358 ÷ 39=60 r 18
Estimate, multiply back, subtract the remainder.
- 01
Estimate by leading digits; refine quotient digit-by-digit
Apply this piece of the shortcut — running quotient 2358.
- →
= 60 r 18
Benjamin, Secrets of Mental Math — estimated long division
2547 ÷ 28=90 r 27
Estimate, multiply back, subtract the remainder.
- 01
Estimate by leading digits; refine quotient digit-by-digit
Apply this piece of the shortcut — running quotient 2547.
- →
= 90 r 27
Benjamin, Secrets of Mental Math — estimated long division
1336 ÷ 36=37 r 4
Estimate, multiply back, subtract the remainder.
- 01
Estimate by leading digits; refine quotient digit-by-digit
Apply this piece of the shortcut — running quotient 1336.
- →
= 37 r 4
Benjamin, Secrets of Mental Math — estimated long division
Talking Points
- •Round the divisor for an estimate, then adjust.
Week 4 · Division & Estimation
Mental division, overshooting, and guesstimation.
- →Mental division
- →Overshooting methods
- →Guesstimation
Sample Problems · Week 4
One simple and one intermediate problem to preview the week.
Simple · Day 1
79 ÷ 3=26 r 1
Intermediate · Day 5
8.25% tax on $47=≈ $3.88