Question

20,9 - 13 7/10 и 6 8/25 + 1,28= ? Хелп 6 класс

Answer 1

20,9 - 13 7/10 = 20,9 - 13,7 = 7,2

6 8/25 + 1,28 = 6 32/100 + 1,28 = 6,32 + 1,28 = 7,6

Answer 2

Sure, let's solve this math problem step by step:

20,9 - 13 7/10

First, we need to convert the mixed number 13 7/10 into an improper fraction: 13 7/10 = (10 * 13 + 7)/10 = 137/10

So, the subtraction becomes: 20,9 - 137/10

To subtract these two values, we need to have a common denominator. We can convert 20,9 to a fraction with a denominator of 10 by multiplying both the numerator and denominator by 10: 20,9 = 209/10

Now, we can subtract the two fractions with the same denominator: 209/10 - 137/10 = 72/10 = 7 2/10 = 7,2

Therefore, 20,9 - 13 7/10 = 7,2

Next, let's solve the expression:

6 8/25 + 1,28

We can first convert 1,28 to a fraction by placing it over 1,00: 1,28 = 1,28/1,00

Then, we convert the mixed number 6 8/25 into an improper fraction: 6 8/25 = (25 * 6 + 8)/25 = 158/25

Now, we can add the two fractions with different denominators: 158/25 + 1,28/1,00

To add these two fractions, we need to have a common denominator. We can convert 1,28 to a fraction with a denominator of 25 by multiplying both the numerator and denominator by 25: 1,28/1,00 = 128/100 = 32/25

Now, we can add the two fractions with the same denominator: 158/25 + 32/25 = 190/25 = 7 15/25 = 7 3/5

Therefore, 6 8/25 + 1,28 = 7,6

Finally, we can substitute the results back into the original expression:

20,9 - 13 7/10 + 6 8/25 + 1,28 = 7,2 + 7,6 = 14,8

So, the final answer is 14,8.