Solve the exercise:
84:4=
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Solve the exercise:
84:4=
There are several ways to solve the following exercise,
We will present two of them.
In both ways, we begin by decomposing the number 84 into smaller units; 80 and 4.
Subsequently we are left with only the 80.
Continuing on with the first method, we will then further decompose 80 into smaller units;
We know that:
And therefore, we are able to reduce the exercise as follows:
Eventually we are left with
which is equal to 20
In the second method, we decompose 80 into the following smaller units:
We know that:
And therefore:
which is also equal to 20
Now, let's remember the 1 from the first step and add it in to our above answer:
Thus we are left with the following solution:
21
\( 140-70= \)
Breaking 84 into 80 + 4 makes division much easier! It's harder to see that 84 ÷ 4 = 21 directly, but easy to see that 80 ÷ 4 = 20 and 4 ÷ 4 = 1.
Absolutely! You could use 40 + 40 + 4 or even 60 + 24. As long as your parts add up to 84 and are easy to divide by 4, any breakdown works!
Use the inverse operation! Since division and multiplication are opposites, check that 21 × 4 = 84. If it equals your original number, you're correct!
No problem! Use repeated subtraction or think of it as "how many groups of 4 can I make from 84?" You can also use the decomposition method shown here.
With practice, you'll recognize patterns! Since 8 ÷ 4 = 2, you can think: 84 has 8 tens and 4 ones, so 84 ÷ 4 = 20 + 1 = 21.
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