Ask for full boxes
53 pencils, 8 per box.
建立除法故事:商与余数
Turn equal groups and leftovers into one complete equation. Learn the four parts of a division story, the remainder rule, and how to rebuild a missing quantity.
Work through one or two missions at a time. First predict an answer on paper, then use a laboratory to test it. If stuck, open the local hint and then the reasoning. Try the workshop yourself. After checking an attempt, you can choose to review worked solutions. Every explanation you need is on this page; external chat is optional.
Division with a remainder begins with a physical story: make as many complete equal groups as possible, then count the leftover objects.
For a nonnegative whole-number dividend and a positive whole-number divisor, division can be written as:
The worked example chapter writes the same relationship as a = b × q + r, with 0 ≤ r < b.
Count full groups first.
23=5×4+3: four groups use 20; three counters remain.
Each number has a different job. Keeping the vocabulary attached to the equation prevents quotient–remainder mix-ups later.
Read each number’s job.
In 29=6×4+5, 29 is the total (dividend), 6 the group size (divisor), 4 the full-group count (quotient), and 5 the remainder.
The equation is a check as well as a model. Multiply the divisor by the quotient, then add the remainder; the result must return to the dividend.
Example: 8 × 5 + 7 = 47.
Example: 47 ÷ 8 = 5 remainder 7.
Multiply before adding.
8×5=40; 40+7=47. The leftover 7 is smaller than group size 8.
If the leftover is large enough to make another full group, the division story is not finished.
For divisor 7, the only valid remainders are:
A full group cannot stay in the leftovers.
With divisor 7, remainders run from 0 to 6. In 31=6×4+7, regroup the 7 as 6+1 to obtain 31=6×5+1.
Remainder zero is still part of the same equation. It means every object fits into a complete group.
Nothing is left. We can also write:
One object remains after four full groups.
Compare with a multiple of 6.
24=6×4+0, 25=6×4+1, and an exact division has remainder 0. You must type 0, not leave the field empty.
Enter three known quantities and choose the fourth to find, then check the remainder rule. Most valid inputs determine one answer. If the missing divisor is multiplied by a zero quotient, however, several divisors may work; the solver explains that case.
A later guided problem uses:
The same four-part language lets students recover the dividend from the divisor, quotient, and remainder.
Rebuild the total.
392=47×8+16. Check 47×8=376, then add 16; 16<47.
Fix the divisor and a valid remainder. Let the quotient run through 0, 1, 2, and so on. The first family member is the remainder itself; each next member adds one whole divisor.
Each number leaves remainder 4 when divided by 6.
Adding the divisor keeps the remainder unchanged.
Move one whole group along the family.
For remainder 4 modulo 6, use N=6q+4. After 28 comes 34; 46=6×7+4.
The arithmetic may be the same, but the final sentence depends on the question: full containers, leftover objects, or containers needed altogether.
53 pencils, 8 per box.
The same packing story.
The five leftovers still need a box.
A practice problem says that dividing 310 by an unknown two-digit divisor leaves remainder 37.
Before finding the divisor, one fact is immediate:
Read what the story asks you to count.
53=8×6+5 means six full boxes and five items left. Packing everything needs seven boxes. A claimed remainder 37 needs divisor greater than 37.
Use the complete division story. Correct all eight responses to complete the workshop.
Write the division equation or identify the repeated change first. Use the nearby mission hints for the matching method. For “all possible” answers, list the candidates systematically and explain why no other candidate can pass. Check every answer in the original story.
Try these questions with the examples covered. Complete Missions 1–8, earn 8/8 in the workshop, and earn 5/5 here to unlock your certificate. Reflection is optional and ungraded.
Certificate of completion
has completed Lesson 16.1 and demonstrated accurate use of the division equation, quotient, remainder, and remainder bound.
74=8×9+2. A divisor of 13 allows 0 through 12. Add 7 to 41 to reach 48. Nine full boxes plus one partial box hold all 74 counters.
If you used this explanation, close it and solve the questions again on paper. Explain why each remainder is smaller than its divisor.
Chapter 16 opens with the division equation a = b × q + r and the condition 0 ≤ r < b, then focuses on nonzero-remainder problems. This lesson develops that opening into a complete student learning sequence with equal-group models, vocabulary, equation building, exact-division comparison, missing-value tools, and objective practice.