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In order to simplify the resolution process, we begin by using the distributive property for 140:
We then rearrange the exercise using the substitution property into a more practical form:
Lastly we solve the exercise from left to right:
70
\( 100-(30-21)= \)
Breaking numbers into place values makes subtraction clearer! When you see 140-70, you can rearrange it as (100-70)+40, which gives you easy mental math: 30+40=70.
Absolutely! 140-70=70 works perfectly. The rearranging method is just one strategy to help when direct subtraction feels tricky.
Remember: in 140-70, you're taking away 70 from 140. Think of it as "I had 140, I gave away 70, how much do I have left?"
Use addition to check! Take your answer and add it to the number you subtracted: 70+70=140. If you get the original number, you're right!
It's using the distributive property to make calculation easier. Since 140=100+40, we can write 140-70 as (100+40)-70 = 100-70+40.
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