What is 21x10?

What is the multiples of 10-strategy for division?

876 divided by 21. You can use your knowledge of the base 10 system to say: 21X10=210(too small) 21X20=420(still too small) 21X30=630(let me subtract 876-630=246, I'm getting close) 21X40=840 and when I subtract I get a remainder of 36. I can make 1 more group of 21. 36-21=15. So my answer is 41 with a remainder of 15. You can use multiples of 100,100, etc. for larger numbers.