Calculate the size of $\angle ABC$∠ABC.
In the following figure, $\angle RTV$∠RTV=$49$49° and $\angle UTV$∠UTV=$26$26°. Find $\angle RTU$∠RTU.
Use a range of additive and simple multiplicative strategies with whole numbers, fractions, decimals, and percentages.
Record and interpret additive and simple multiplicative strategies, using words, diagrams, and symbols, with an understanding of equality